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25 Dec 2000

Volume 77, Issue 26, pp. 4247-4436

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Direct evidence for 8-interstitial-controlled nucleation of extended defects in c-Si

F. Schiettekatte, S. Roorda, R. Poirier, M. O. Fortin, S. Chazal, and R. Héliou

Appl. Phys. Lett. 77, 4322 (2000); http://dx.doi.org/10.1063/1.1336163 (3 pages) | Cited 2 times

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The areal density of extended defects in P-implanted and annealed Si is observed to increase with ion dose to the power 8. A simple model based on Poisson statistics applied to point defects created during ion implantation shows that such a dependence corresponds to enhanced stability of interstitial clusters consisting of at least eight interstitial atoms, and it implies an interstitial “clustering” radius of 0.8 nm. The direct observation of n = 8 confirms the curious behavior observed earlier in transient-enhanced diffusion of B in Si, and provides a quantitative explanation of the threshold dose for the formation of extended defects in ion-implanted Si. © 2000 American Institute of Physics.
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61.72.Nn Stacking faults and other planar or extended defects
61.72.J- Point defects and defect clusters
61.72.uf Ge and Si
61.82.Fk Semiconductors

Grain boundary filtration by selective nucleation and solid phase epitaxy of Ge through planar constrictions

Hiroshi Tanabe, Claudine M. Chen, and Harry A. Atwater

Appl. Phys. Lett. 77, 4325 (2000); http://dx.doi.org/10.1063/1.1333682 (3 pages) | Cited 3 times

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We have proposed and experimentally demonstrated a grain boundary filtration technique for unseeded fabrication of single grain semiconductor films on amorphous substrates by using patterned P-doped amorphous Ge films with In-induced selective nucleation and solid phase epitaxy. The patterns consist of a small Ge island seed region including a deposited metal selective nucleation site, a narrow seed region, and a single grain region consisting of a main rectangular island. Transmission electron microscopy revealed lateral epitaxy initiated at the edge of the selective nucleation site and the grain selection process through the narrow seed selection region produced only one grain orientation at the entrance of the main island. Single grain regions as large as 100 μm2 with only a few low-angle boundaries were formed at 400 °C without spontaneous nucleation. © 2000 American Institute of Physics.
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81.15.Np Solid phase epitaxy; growth from solid phases
61.72.Mm Grain and twin boundaries
81.05.Cy Elemental semiconductors
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.

Spherical SiGe quantum dots prepared by thermal evaporation

Yu-Cheng Liao, Shih-Yen Lin, Si-Chen Lee, and Chih-Ta Chia

Appl. Phys. Lett. 77, 4328 (2000); http://dx.doi.org/10.1063/1.1334649 (2 pages) | Cited 6 times

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SiGe alloy quantum dots with spherical shape have been synthesized by the thermal evaporation method. The shape and structure of these dots have been investigated. Transmission electron microscopy images show that they have an average diameter of about 15 nm, and their cores are crystalline. The composition of these dots could be extracted from the Raman peak position of the silicon TO phonon. © 2000 American Institute of Physics.
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81.15.-z Methods of deposition of films and coatings; film growth and epitaxy
78.30.Hv Other nonmetallic inorganics
78.66.Fd III-V semiconductors
63.20.D- Phonon states and bands, normal modes, and phonon dispersion

Compressive strength of synthetic diamond grits containing metallic nanoparticles

J. H. P. Watson, Z. Li, and A. M. Hyde

Appl. Phys. Lett. 77, 4330 (2000); http://dx.doi.org/10.1063/1.1334352 (2 pages) | Cited 3 times

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Synthetic diamonds made by high-temperature and high-pressure synthesis using an Fe–Co solvent/catalyst leave nanoparticles of the solvent/catalyst within the diamond matrix. These nanoparticles strongly affect the magnetic properties of the diamond. The magnetization versus field was compatible with the response of superparamagnetic particles. The mean size and separation of the inclusions were calculated. The inclusion size was found to be constant to within 10%, whereas the saturation magnetization varied by a factor of 100. A transmission electron microscope image of a single inclusion from a Fe–Co/diamond grit showed a dark, iron-rich core surrounded by a halo of material of intermediate contrast to the lighter diamond matrix. The size of the core is consistent with the magnetization measurements while the halo is of similar size to that determined by small-angle neutron scattering. The compressive strength increased linearly with the inclusion separation. © 2000 American Institute of Physics.
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81.05.ub Fullerenes and related materials
81.40.Lm Deformation, plasticity, and creep
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
61.72.Qq Microscopic defects (voids, inclusions, etc.)
62.20.F- Deformation and plasticity
75.50.Tt Fine-particle systems; nanocrystalline materials

Amorphization and anisotropic fracture dynamics during nanoindentation of silicon nitride: A multimillion atom molecular dynamics study

Phillip Walsh, Rajiv K. Kalia, Aiichiro Nakano, Priya Vashishta, and Subhash Saini

Appl. Phys. Lett. 77, 4332 (2000); http://dx.doi.org/10.1063/1.1328371 (3 pages) | Cited 16 times

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Molecular dynamics simulations of nanoindentation of 10 million atom α-Si3N4 films using a rigid indenter are reported. Local pressure distributions and configuration images of the plastically deformed region are presented. Residual tensile pressures correspond to voids and cracks that separate regions of compacted, plastically deformed material and elastically recovered crystalline material. Structural analysis shows that pile-up material on the surface and deformed material under the indenter is amorphous. With this indenter geometry, Si3N4 deforms primarily by amorphization, which is arrested by cracking at the indenter corners and piling-up of material along the indenter sides. Indentation fracture exhibits anisotropic behavior consistent with the orientation-dependent fracture toughness values. © 2000 American Institute of Physics.
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68.60.Bs Mechanical and acoustical properties
81.40.Np Fatigue, corrosion fatigue, embrittlement, cracking, fracture, and failure
62.20.Qp Friction, tribology, and hardness
61.43.Er Other amorphous solids
81.40.Lm Deformation, plasticity, and creep
62.20.F- Deformation and plasticity
61.72.Qq Microscopic defects (voids, inclusions, etc.)
81.05.Je Ceramics and refractories (including borides, carbides, hydrides, nitrides, oxides, and silicides)
68.35.Gy Mechanical properties; surface strains
61.43.Bn Structural modeling: serial-addition models, computer simulation

Magnetoluminescence studies in InGaP alloys

J. Zeman, G. Martinez, K. K. Bajaj, I. Krivorotov, and K. Uchida

Appl. Phys. Lett. 77, 4335 (2000); http://dx.doi.org/10.1063/1.1334648 (3 pages) | Cited 8 times

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We have measured both the diamagnetic shift and the linewidth of an excitonic transition in In0.48Ga0.52P as a function of magnetic field up to 22 T at 4.2 K using photoluminescence spectroscopy. The sample was grown on a GaAs substrate using low-pressure metalorganic vapor phase epitaxy at 700 °C. The substrate was misoriented by 15° from [001] towards [011] direction. We find that the variations of both the diamagnetic shift and the linewidth with magnetic field are about one half of those reported earlier [E. D. Jones, R. P. Schneider, Jr., S. M. Lee, and K. K. Bajaj, Phys. Rev. B 46, 7225 (1992)] in a In0.48Ga0.52P sample grown with only 2° misorientation and also those calculated using a free exciton model. We suggest that this behavior may be due to the fact that our sample was grown with much larger misorietation. We have calculated both of these variations using a model in which we assume that in this sample the hole is completely localized and find an excellent agreement with the observed data. © 2000 American Institute of Physics.
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78.55.Cr III-V semiconductors
78.20.Ls Magneto-optical effects
71.35.Ji Excitons in magnetic fields; magnetoexcitons
78.66.Fd III-V semiconductors
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Electrical and optical properties of strongly reduced epitaxial BaTiO3−x thin films

Tong Zhao, Zheng-Hao Chen, Fan Chen, Hui-Bin Lu, Guo-Zhen Yang, and Huan-Sheng Cheng

Appl. Phys. Lett. 77, 4338 (2000); http://dx.doi.org/10.1063/1.1334353 (3 pages) | Cited 16 times

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A series of BaTiO3−x (x = 0, 0.07, 0.18, and 0.48) thin films with c-axis oriented tetragonal perovskite structures were epitaxially grown on SrTiO3 (100) and MgO (100) substrates by laser molecular-beam epitaxy under various oxygen pressures. The electrical conductivity of the deposited thin films increases with decreasing the oxygen pressure. A metallic conduction is observed in the oxygen most deficient BaTiO2.52 thin film whose oxygen content (2.52) and electrical resistivity (6.0×10−5 Ω cm) are both the minimum values among literature. An optical absorption peak is observed in each oxygen deficient BaTiO3−x thin film. The peak position shifts to lower energy, and the peak width becomes larger with decreasing the oxygen pressure. The influence of oxygen pressure on the electrical and optical properties in the reduced BaTiO3−x thin films is discussed. © 2000 American Institute of Physics.
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77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates
77.55.-g Dielectric thin films
78.66.Nk Insulators
73.61.Ng Insulators
77.80.-e Ferroelectricity and antiferroelectricity
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
78.40.Ha Other nonmetallic inorganics

Resonant tunneling diodes made up of stacked self-assembled Ge/Si islands

O. G. Schmidt, U. Denker, K. Eberl, O. Kienzle, F. Ernst, and R. J. Haug

Appl. Phys. Lett. 77, 4341 (2000); http://dx.doi.org/10.1063/1.1332817 (3 pages) | Cited 13 times

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Multiple layers of self-assembled Ge/Si islands are used for resonant tunneling diodes (RTDs). The extremely closely stacked Ge nanostructures form vertical channels with energetically deep thermalization layers and high Si double barriers. Two resonances are found in the RTD current–voltage curve, which are attributed to the heavy-heavy hole (hh) and heavy-light hole (lh) transition. The lh resonance shows negative differential resistance up to 50 K. With increasing magnetic field, the lh resonance slightly shifts to higher voltages. © 2000 American Institute of Physics.
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85.30.Kk Junction diodes
85.30.Mn Junction breakdown and tunneling devices (including resonance tunneling devices)
85.30.De Semiconductor-device characterization, design, and modeling
85.35.Be Quantum well devices (quantum dots, quantum wires, etc.)

Electric-field-dependent carrier capture and escape in self-assembled InAs/GaAs quantum dots

P. W. Fry, J. J. Finley, L. R. Wilson, A. Lemaître, D. J. Mowbray, M. S. Skolnick, M. Hopkinson, G. Hill, and J. C. Clark

Appl. Phys. Lett. 77, 4344 (2000); http://dx.doi.org/10.1063/1.1334363 (3 pages) | Cited 34 times

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Photoluminescence and complementary photocurrent spectroscopy, both as a function of electric field, are used to probe carrier capture and escape mechanisms in InAs/GaAs quantum dots. Carrier capture from the GaAs matrix is found to be highly field sensitive, being fully quenched in fields of only 15 kV/cm. For fields less than 20 kV/cm, carriers excited in the wetting layer are shown to be captured by the dots very effectively, whereas for fields in excess of 50 kV/cm tunnel escape from the wetting layer into the GaAs continuum is dominant. For excitation directly into the dots, radiative recombination dominates up to 100 kV/cm. © 2000 American Institute of Physics.
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72.40.+w Photoconduction and photovoltaic effects
73.50.Pz Photoconduction and photovoltaic effects
78.20.Jq Electro-optical effects
73.50.Gr Charge carriers: generation, recombination, lifetime, trapping, mean free paths

Hot carrier recombination model of visible electroluminescence from metal–oxide–silicon tunneling diodes

C. W. Liu, S. T. Chang, W. T. Liu, Miin-Jang Chen, and Ching-Fuh Lin

Appl. Phys. Lett. 77, 4347 (2000); http://dx.doi.org/10.1063/1.1332825 (3 pages) | Cited 10 times

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We report the visible electroluminescence at room temperature from metal–oxide–silicon tunneling diodes. As biased in the Fowler–Nordheim regime, the electrons tunnel from the gate electrode through the ultrathin oxide and reach the Si anode with sufficiently high energy. The hot electrons cause the impact ionization, and generate the secondary hot electrons and hot holes in Si substrates. The visible light comes from the radiative recombination between the secondary hot electrons and hot holes, and the hot carrier recombination model can fit the visible electroluminescence spectra. © 2000 American Institute of Physics.
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85.60.Jb Light-emitting devices
85.30.Mn Junction breakdown and tunneling devices (including resonance tunneling devices)
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
78.60.Fi Electroluminescence
73.50.Fq High-field and nonlinear effects

Correlation between the gate bias dependence of the probability of anode hole injection and breakdown in thin silicon dioxide films

Piyas Samanta and C. K. Sarkar

Appl. Phys. Lett. 77, 4350 (2000); http://dx.doi.org/10.1063/1.1332838 (3 pages) | Cited 1 time

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Hole injection from the anode in thin silicon dioxide (SiO2) films in n+-polycrystalline silicon gate–oxide–silicon structures has been theoretically investigated during high-field Fowler–Nordheim electron injection from both substrate (positive gate bias) and gate (negative gate bias). Theoretical results of the gate bias dependence of the probability of anode hole injection per injected electron αh as a function of electric field or injection current density are shown to be directly correlated to experimentally observed polarity dependence of destructive breakdown in thin SiO2 films. © 2000 American Institute of Physics.
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77.22.Jp Dielectric breakdown and space-charge effects
77.84.Bw Elements, oxides, nitrides, borides, carbides, chalcogenides, etc.
77.55.-g Dielectric thin films
73.61.Ng Insulators
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
73.50.Fq High-field and nonlinear effects

Current transport mechanism of p-GaN Schottky contacts

Kenji Shiojima, Tomoya Sugahara, and Shiro Sakai

Appl. Phys. Lett. 77, 4353 (2000); http://dx.doi.org/10.1063/1.1332981 (3 pages) | Cited 14 times

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Transient measurements of I–V and depletion layer capacitance were conducted to clarify the leaky current flow mechanism in Ni Schottky contacts formed on Mg-doped p-GaN. We found that carrier capture and emission from acceptor-like deep level defects cause depletion layer width (Wdep) to vary significantly. Upon ionization of the defects by white light, which results in small Wdep, current can go through the Schottky barrier and a leaky I–V curve is observed. Upon filling by current injection, Wdep becomes larger and the large original Schottky barrier height is seen. The time constant of carrier emission is as long as 8.3×103 min. © 2000 American Institute of Physics.
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73.30.+y Surface double layers, Schottky barriers, and work functions
73.40.Ns Metal-nonmetal contacts
73.20.Hb Impurity and defect levels; energy states of adsorbed species
71.55.Eq III-V semiconductors

Terahertz-frequency electronic coupling in vertically coupled quantum dots

P. Boucaud, J. B. Williams, K. S. Gill, M. S. Sherwin, W. V. Schoenfeld, and P. M. Petroff

Appl. Phys. Lett. 77, 4356 (2000); http://dx.doi.org/10.1063/1.1334912 (3 pages) | Cited 11 times

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We have studied terahertz absorption of samples containing two layers of self-aligned, self-assembled InAs quantum dots separated by a thin GaAs barrier. The vertically coupled dots were charged with electrons by applying a voltage bias between a metal gate and a doped layer beneath the dots. For a positive gate bias corresponding to flatband conditions, an absorption peak was observed near 10 meV (2.4 THz). The absorption is attributed to the inhomogeneously broadened transition between the quantum mechanically split levels (bonding and antibonding states) in the vertically coupled quantum dots. © 2000 American Institute of Physics.
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78.66.Fd III-V semiconductors
78.30.Fs III-V and II-VI semiconductors

Free electron density and mobility in high-quality 4H–SiC

J. Pernot, S. Contreras, J. Camassel, J. L. Robert, W. Zawadzki, E. Neyret, and L. Di Cioccio

Appl. Phys. Lett. 77, 4359 (2000); http://dx.doi.org/10.1063/1.1332102 (3 pages) | Cited 20 times

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The free electron density and low-field electron mobility of 4H–SiC is examined in the temperature range 35–900 K. In good samples the electron density is constant in the temperature range 300–900 K, which offers interesting possibilities for high temperature sensor applications. On the best sample an experimental electron mobility of 12 400 cm2/V s at 50 K is found. A complete description of the temperature dependence of the electron density and mobility is given. We take into account the effects of the two inequivalent lattice sites as well as the valley–orbit splitting of the ground state at the hexagonal sites. The dependence of room-temperature mobility on electron concentration is established, described theoretically and compared with the results obtained by different authors. © 2000 American Institute of Physics.
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73.61.Le Other inorganic semiconductors
71.20.Nr Semiconductor compounds
73.50.Dn Low-field transport and mobility; piezoresistance
73.50.Jt Galvanomagnetic and other magnetotransport effects (including thermomagnetic effects)

Electronic properties of the diamond films with nitrogen impurities: An x-ray absorption and photoemission spectroscopy study

Y. D. Chang, A. P. Chiu, W. F. Pong, M.-H. Tsai, Y. K. Chang, Y. Y. Chen, J. W. Chiou, C. J. Jan, P. K. Tseng, R. T. Wu, S. C. Chung, K. L. Tsang, I. N. Lin, and H. F. Cheng

Appl. Phys. Lett. 77, 4362 (2000); http://dx.doi.org/10.1063/1.1334916 (3 pages)

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X-ray absorption near-edge structure (XANES) measurements have been performed for nitrogen (N) containing diamond films with three different N concentrations at the C K-edge using the sample drain current mode. The C K-edge XANES spectra of these diamond films resemble that of the pure diamond regardless of the N concentration, which suggests that the overall bonding configuration of the C atom is unaltered. N impurities are found to reduce the intensities of both the sp2- and sp3-bond derived resonance features in the XANES spectra. The valence-band photoelectron spectra indicate that N atoms cause the broadening of the valence band σ- and π-bond features and the enhancement and reduction of the σ- and π-bond features, respectively. © 2000 American Institute of Physics.
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78.70.Dm X-ray absorption spectra
79.60.Dp Adsorbed layers and thin films
71.20.Mq Elemental semiconductors
71.55.Cn Elemental semiconductors

Thermal dynamics of VO2 films within the metal–insulator transition: Evidence for chaos near percolation threshold

L. A. L. de Almeida, G. S. Deep, A. M. N. Lima, and H. Neff

Appl. Phys. Lett. 77, 4365 (2000); http://dx.doi.org/10.1063/1.1334917 (3 pages) | Cited 14 times

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The thermal dynamics of thin vanadium dioxide films at the martensitic metal–insulator phase transition has been evaluated experimentally by thermal excitation spectroscopy. Over the transition region, the device becomes highly nonlinear, and its bolometric performance is affected. At low thermal cycling rates for a temperature around the percolation threshold, the device stochastically switches into an unusual pattern. The originally smooth and monotonic shape of the R(T) curve for minor loops suddenly becomes unstable and unpredictable. By direct observation of at least two strange attractors, the phenomenon clearly has been identified as chaotic. Bolometric performance of VO2 based devices in the transition region may suffer strong degradation for low thermal cycling rates. In this region, sensor responsivity for periodic thermal excitation is significantly reduced. Resistance noise is 1/f-type and self-generated oscillations were observed at frequency <10−2 Hz. © 2000 American Institute of Physics.
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73.50.Td Noise processes and phenomena
07.57.Kp Bolometers; infrared, submillimeter wave, microwave, and radiowave receivers and detectors
68.60.Dv Thermal stability; thermal effects
71.30.+h Metal-insulator transitions and other electronic transitions
72.60.+g Mixed conductivity and conductivity transitions
05.40.Ca Noise
72.70.+m Noise processes and phenomena
05.45.-a Nonlinear dynamics and chaos

Correlation between the gap energy and size of single InAs quantum dots on GaAs(001) studied by scanning tunneling spectroscopy

T. Yamauchi, Y. Matsuba, L. Bolotov, M. Tabuchi, and A. Nakamura

Appl. Phys. Lett. 77, 4368 (2000); http://dx.doi.org/10.1063/1.1333397 (3 pages) | Cited 13 times

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Scanning tunneling spectroscopy has been used to study quantum-size effects on the electronic structure of InAs quantum dots (QDs) in correlation with their morphologies. The measured gap energy increases with decreasing dot height in the range of 3.4–7.6 nm. Comparison between the observed height dependence and calculation based on a quantum disk model indicates that the gap energy of a single InAs QD is mainly determined by the quantum confinement in the vertical direction of the QD. © 2000 American Institute of Physics.
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68.35.B- Structure of clean surfaces (and surface reconstruction)
68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties
68.37.Ef Scanning tunneling microscopy (including chemistry induced with STM)
68.37.Ps Atomic force microscopy (AFM)
68.37.Rt Magnetic force microscopy (MFM)
68.37.Uv Near-field scanning microscopy and spectroscopy

Temperature and partial oxygen pressure role on the electrical conductivity of Bi12Ti0.7Ga0.3O20 single crystal

S. Lanfredi, J. F. Carvalho, and A. C. Hernandes

Appl. Phys. Lett. 77, 4371 (2000); http://dx.doi.org/10.1063/1.1336165 (3 pages) | Cited 3 times

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The electrical conduction properties of Bi12Ti0.7Ga0.3O20 (BTGaO) single crystal was investigated by impedance spectroscopy. The measurements were performed in the range of 100–400 °C and in a frequency range of 5–1.3×107 Hz. The effect of partial oxygen pressure on the electric conductivity was investigated from 1 to 10−6 atm. The data are presented in a Nyquist diagram plot, from which the electric resistance was determined. The electric conductivity follows the Arrhenius law, with an activation energy of 0.55 eV. The change in conductivity caused by oxygen pressure showed that BTGaO is a p-type semiconductor, according to the relation σ α PO2+1/4. The dielectric constant value was equal to 50. The dielectric behavior of BTGaO does not depend on the temperature and the partial oxygen pressure. © 2000 American Institute of Physics.
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72.30.+q High-frequency effects; plasma effects
72.80.Ga Transition-metal compounds
77.22.Ch Permittivity (dielectric function)
77.84.Bw Elements, oxides, nitrides, borides, carbides, chalcogenides, etc.

Impact ionization coefficients of Al0.8Ga0.2As

B. K. Ng, J. P. R. David, S. A. Plimmer, M. Hopkinson, R. C. Tozer, and G. J. Rees

Appl. Phys. Lett. 77, 4374 (2000); http://dx.doi.org/10.1063/1.1336556 (3 pages) | Cited 10 times

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The impact ionization coefficients in bulk Al0.8Ga0.2As have been determined from photomultiplication measurements over the electric field range of 328–519 kV/cm. Unlike in AlxGa1−xAs (x ⩽ 0.6), where the electron to hole ionization coefficients ratios (1/k) are less than 2, the 1/k value in Al0.8Ga0.2As was found to be greater than 10. Excess noise measurements corroborated the multiplication results, suggesting that this material may be a suitable multiplication medium for low noise avalanche photodiodes. © 2000 American Institute of Physics.
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72.80.Ey III-V and II-VI semiconductors
73.61.Ey III-V semiconductors
73.50.Fq High-field and nonlinear effects
72.20.Ht High-field and nonlinear effects
85.60.Dw Photodiodes; phototransistors; photoresistors
72.70.+m Noise processes and phenomena
73.50.Td Noise processes and phenomena

Growth and characterization of low-temperature grown GaN with high Fe doping

H. Akinaga, S. Németh, J. De Boeck, L. Nistor, H. Bender, G. Borghs, H. Ofuchi, and M. Oshima

Appl. Phys. Lett. 77, 4377 (2000); http://dx.doi.org/10.1063/1.1335547 (3 pages) | Cited 38 times

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We succeeded in growing highly Fe-doped GaN films by solid-source molecular beam epitaxy using an electron-cyclotron-resonance microwave nitrogen plasma. The substrate temperature was in the range of 380–520 °C. The samples were analyzed by x-ray diffraction and transmission electron microscopy, and showed hexagonal (wurtzite) or cubic (zincblende) structure or a mixture of both phases. The Fe concentration was on the order of 1019 cm−3 and extended x-ray absorption fine structure data show that the Fe is substituting the Ga in GaN. The magnetization measurements as a function of temperature reveal ferromagnetic properties below 100 K for the sample grown at the lowest temperature. © 2000 American Institute of Physics.
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75.50.Pp Magnetic semiconductors
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
75.70.Ak Magnetic properties of monolayers and thin films
73.61.Ey III-V semiconductors
81.05.Ea III-V semiconductors
75.50.Dd Nonmetallic ferromagnetic materials
78.70.Dm X-ray absorption spectra
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects

Microscopic carrier dynamics of quantum-well-based light storage cells

S. K. Zhang, P. V. Santos, R. Hey, A. Garcia-Cristóbal, and A. Cantarero

Appl. Phys. Lett. 77, 4380 (2000); http://dx.doi.org/10.1063/1.1336160 (3 pages) | Cited 6 times

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The dynamics of storage and recombination of electron–hole pairs in quantum-well-based light memory cells driven by high-frequency electric fields is investigated by spatially and time-resolved photoluminescence spectroscopy. In these cells, a laterally modulated potential is used to ionize and spatially separate photogenerated electron–hole pairs. The temporal and spatial dependence of the carrier dynamics depends not only on the modulated potential, but also on the transport properties of electrons and holes. © 2000 American Institute of Physics.
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73.50.Pz Photoconduction and photovoltaic effects
73.50.Gr Charge carriers: generation, recombination, lifetime, trapping, mean free paths
73.50.Mx High-frequency effects; plasma effects
78.47.-p Spectroscopy of solid state dynamics

Temperature dependence of surface photovoltage of bulk semiconductors and the effect of surface passivation

Shouvik Datta, M. R. Gokhale, A. P. Shah, B. M. Arora, and Shailendra Kumar

Appl. Phys. Lett. 77, 4383 (2000); http://dx.doi.org/10.1063/1.1336548 (3 pages) | Cited 2 times

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Surface photovoltage (SPV) of n-GaAs decreases both above and below a certain transition temperature. We explain this phenomenon in terms of a Schottky contact based model and relative dominance of thermal and nonthermal parts of the dark current. This also explains the observed increase of SPV of p-GaAs below room temperature. Our analysis is further confirmed from the temperature dependence of the SPV measurements on p-InP and n-InP samples. Surface passivation is seen to lower the transition temperature of n-GaAs. © 2000 American Institute of Physics.
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73.25.+i Surface conductivity and carrier phenomena
72.40.+w Photoconduction and photovoltaic effects
81.65.Rv Passivation
73.30.+y Surface double layers, Schottky barriers, and work functions

Incorporation of Mg in GaN grown by plasma-assisted molecular beam epitaxy

Gon Namkoong, W. Alan Doolittle, and April S. Brown

Appl. Phys. Lett. 77, 4386 (2000); http://dx.doi.org/10.1063/1.1334942 (3 pages) | Cited 6 times

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We describe dramatically decreased Mg incorporation in GaN above a critical Mg flux. Secondary ion mass spectroscopy analysis showed a linear increase in Mg concentration up to a flux equivalent to 8.0×10−10 Torr beam equivalent pressure (BEP) and 1.6×10−9 Torr BEP at 550 and 615 °C respectively, beyond which the Mg incorporation was reduced by factors of 10 for 550 °C, and 2 for 615 °C. In a transition region between this critical flux and higher flux, a time dependent incorporation phenomenon was observed. An increase in the GaN growth rate was also observed in the presence of Mg above the critical flux. © 2000 American Institute of Physics.
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61.72.uj III-V and II-VI semiconductors
81.05.Ea III-V semiconductors
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
82.80.Ms Mass spectrometry (including SIMS, multiphoton ionization and resonance ionization mass spectrometry, MALDI)

Modeling of steady-state field distributions in blocked impurity band detectors

N. M. Haegel, J. E. Jacobs, and A. M. White

Appl. Phys. Lett. 77, 4389 (2000); http://dx.doi.org/10.1063/1.1336558 (3 pages) | Cited 5 times

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Steady-state electric field and carrier distributions are calculated for blocked impurity band (BIB) detectors in the absence of external illumination. The results illustrate the role of space charge in the blocking layer. Calculations are presented for Ge:Ga, though the input is easily modified for other materials. The numerical model allows for observation of the effect of spatial doping variations and interface gradients. The BIB field distribution is highly dependent on the purity and compensation in the blocking layer, as well as interface sharpness. In some cases, space charge effects can cause a collapse of the field at the blocker/absorber interface or the contact and resultant low field regions in the blocking layer. © 2000 American Institute of Physics.
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71.55.Cn Elemental semiconductors
72.80.Cw Elemental semiconductors
73.61.Cw Elemental semiconductors
72.20.Ht High-field and nonlinear effects
73.50.Fq High-field and nonlinear effects
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
73.50.Gr Charge carriers: generation, recombination, lifetime, trapping, mean free paths

Decrease in gap states at ultrathin SiO2/Si interfaces by crown-ether cyanide treatment

Hikaru Kobayashi, Akira Asano, Masao Takahashi, Kenji Yoneda, and Yoshihiro Todokoro

Appl. Phys. Lett. 77, 4392 (2000); http://dx.doi.org/10.1063/1.1332982 (3 pages) | Cited 19 times

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A simple method to passivate interface states at ultrathin SiO2/Si interfaces is developed. In this method, ultrathin SiO2-covered Si is immersed in a KCN solution containing crown-ether, followed by a rinse in water at 25 °C. The conductance–voltage measurements show that the interface state density is decreased to ∼1/10 by this crown-ether cyanide treatment. The capacitance–voltage measurements show that contamination by K+ ions is effectively avoided by the inclusion of crown-ether. These results demonstrate that crown-ether molecules effectively capture K+ ions and consequently CN− ions effectively may react with defect states, probably forming Si–CN bonds. The passivation of interface states by the cyanide treatment improves the electrical characteristics of metal–oxide–semiconductor tunneling diodes. © 2000 American Institute of Physics.
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73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
73.20.At Surface states, band structure, electron density of states
81.65.Rv Passivation
85.30.Mn Junction breakdown and tunneling devices (including resonance tunneling devices)
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