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1 Dec 1997

Volume 71, Issue 22, pp. 3191-3307

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Noncontact nanosecond-time-resolution temperature measurement in excimer laser heating of Ni–P disk substrates

Shaochen Chen and Costas P. Grigoropoulos

Appl. Phys. Lett. 71, 3191 (1997); http://dx.doi.org/10.1063/1.120286 (3 pages) | Cited 13 times

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The thermal emission from a Ni–P disk substrate heated by a pulsed excimer laser is measured with nanosecond time resolution. A fast InGaAs photodetector is employed to capture the thermal emission signal. The spectral surface reflectivity is simultaneously measured in situ. The transient surface temperature is derived from the spectral thermal emission signal on the basis of Planck’s blackbody radiation intensity distribution. The experimental results and analytical solutions are compared and an important parameter involving the thermal diffusivity and conductivity in the transient temperature response of the material is evaluated. © 1997 American Institute of Physics.
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07.20.Dt Thermometers
06.60.Jn High-speed techniques (microsecond to femtosecond)
78.47.-p Spectroscopy of solid state dynamics
65.90.+i Other topics in thermal properties of condensed matter (restricted to new topics in section 65)
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
66.70.-f Nonelectronic thermal conduction and heat-pulse propagation in solids; thermal waves
61.80.Ba Ultraviolet, visible, and infrared radiation effects (including laser radiation)

Luminescent intrazeolitic Si nanoclusters: Size study by Si K and L2,3 x-ray absorption near-edge structure, x-ray photoelectron and photoluminescence spectroscopies

Jiliang He, Dennis D. Klug, John S. Tse, Chris I. Ratcliffe, and Keith F. Preston

Appl. Phys. Lett. 71, 3194 (1997); http://dx.doi.org/10.1063/1.120287 (3 pages) | Cited 2 times

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A series of intrazeolitic silicon nanoclusters prepared from different Si loadings are investigated by Si K and L2,3 x-ray absorption near-edge structure, x-ray photoelectron and photoluminescence spectroscopies. They exhibit strong room-temperature photoluminescence in the yellow-orange region. It is found that the growth of Si clusters within the pores of zeolite Y is limited to an average size of about 75 Si atoms per unit cell. © 1997 American Institute of Physics.
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78.55.Ap Elemental semiconductors
78.55.Mb Porous materials
61.46.-w Structure of nanoscale materials
78.70.Dm X-ray absorption spectra
79.60.Ht Disordered structures

Photolithographic patterning of vacuum-deposited organic light emitting devices

P. F. Tian, P. E. Burrows, and S. R. Forrest

Appl. Phys. Lett. 71, 3197 (1997); http://dx.doi.org/10.1063/1.120288 (3 pages) | Cited 41 times

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We demonstrate a photolithographic technique to fabricate vacuum-deposited organic light emitting devices. Photoresist liftoff combined with vertical deposition of the emissive organic materials and the metal cathode, followed by oblique deposition of a metal cap, avoids the use of high processing temperatures and the exposure of the organic materials to chemical degradation. The unpackaged devices show no sign of deterioration in room ambient when compared with conventional devices fabricated using low-resolution, shadow mask patterning. Furthermore, the devices are resistant to rapid degradation when operated in air for extended periods. This work illustrates a potential foundation for the volume production of very high-resolution, full color, flat panel displays based on small molecular weight organic light emitting devices. © 1997 American Institute of Physics.
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85.60.Jb Light-emitting devices
42.79.Kr Display devices, liquid-crystal devices
85.60.Pg Display systems
85.40.Hp Lithography, masks and pattern transfer
81.15.-z Methods of deposition of films and coatings; film growth and epitaxy

Characterization of intra-cavity reflections by Fourier transforming spectral data of optically pumped InGaN lasers

Daniel Hofstetter, Linda T. Romano, Robert L. Thornton, David P. Bour, and N. M. Johnson

Appl. Phys. Lett. 71, 3200 (1997); http://dx.doi.org/10.1063/1.120289 (3 pages)

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Fourier analysis of laser emission spectra just above threshold is used to evaluate the impact of structural defects on the emission from optically pumped InGaN lasers. By dry etching a 300-nm-deep groove into the surface of a laser bar, we have modified the emission spectrum of such a device in a controlled manner. The occurrence of sharp features in the Fourier transformed spectrum allowed the identification of the mode spacing corresponding to the full cavity length, as well as to fractions of the full cavity length due to the etched groove. This enables us to identify additional features in the transform spectrum as being due to scattering centers within the waveguide. Identification of the density and strength of such centers is an important capability for the fabrication of blue diode lasers in the gallium–nitride material system. © 1997 American Institute of Physics.
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42.55.Px Semiconductor lasers; laser diodes
78.55.Cr III-V semiconductors
78.66.Fd III-V semiconductors
42.60.Da Resonators, cavities, amplifiers, arrays, and rings
81.65.Cf Surface cleaning, etching, patterning

Theoretical analysis of horizontal shear mode piezoelectric surface acoustic waves in potassium niobate

Kiyoshi Nakamura and Mitsuhiro Oshiki

Appl. Phys. Lett. 71, 3203 (1997); http://dx.doi.org/10.1063/1.120290 (3 pages) | Cited 10 times

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The propagation characteristics of the pure SH (horizontal shear) mode piezoelectric surface acoustic wave (SAW) on rotated Y-cuts about the Z-axis of potassium niobate (KNbO3) are theoretically analyzed. The results show that there exists a SH mode SAW which has a velocity lower than the piezoelectrically inactive Rayleigh mode SAW for most of the rotated cuts. Differing from the so-called Bleustein-Gulyaev wave in 6 mm crystals, the particle displacement of the SH mode SAW on the metalized surface of Y-cut KNbO3 decays with slow oscillation as a function of depth from the substrate surface, while that on the free surface oscillates with a slight decay. The electromechanical coupling factor K2 ranges from a very large value of 0.53 to a relatively small value of 0.026, depending on substrate orientation. © 1997 American Institute of Physics.
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77.65.Dq Acoustoelectric effects and surface acoustic waves (SAW) in piezoelectrics
77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates
68.35.Gy Mechanical properties; surface strains

Mass spectrometric determination of the percent dissociation of a high-density chlorine plasma

G. A. Gaddy, S. F. Webb, and Rik Blumenthal

Appl. Phys. Lett. 71, 3206 (1997); http://dx.doi.org/10.1063/1.120291 (3 pages) | Cited 6 times

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Recent computer modeling of high-density chlorine plasmas has indicated that the gas is highly dissociated. This important prediction has only been recently confirmed by optical measurements, which require either external or internal calibration. Unfortunately, these optical techniques cannot readily be applied to the more chemically complex multicomponent plasmas commonly used in real processing. Using a new mass spectrometric method capable of detecting the local concentrations of both atomic and molecular atomic species within a plasma, a percent molecular dissociation of >85% has been measured in an electron cyclotron resonance chlorine plasma at low pressures. © 1997 American Institute of Physics.
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52.70.Nc Particle measurements
52.25.-b Plasma properties
82.30.Lp Decomposition reactions (pyrolysis, dissociation, and fragmentation)

Evolution of defect-related structure in the x-ray absorption spectra of buried SiNx films

E. C. Paloura

Appl. Phys. Lett. 71, 3209 (1997); http://dx.doi.org/10.1063/1.120292 (3 pages) | Cited 3 times

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Near-edge x-ray absorption fine structure measurements at the N-K edge are used to monitor the evolution of defect-related structure in the spectra of buried SiNx films as a function of the implantation dose. The buried SiNx films were fabricated with implantation of 35 keV 14N+ ions in Si in the dose range 2×1017–2×1018 cm−2. The defect-related resonances RL1 and RL2 appear at 401.1±0.3 and 403.3±0.1 eV, respectively. The RL1 is characteristic of a defect structure in the low and intermediate implantation doses and can be annealed out with an activation energy of 0.5 eV. RL2, which is the signature of excess N in N-rich films and is attributed to transitions of 1s-electrons to unfilled states with p component at a defect site containing a N dangling bond, can be annealed out only after prolonged annealing at 1150 °C. © 1997 American Institute of Physics.
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61.72.uf Ge and Si
81.05.Cy Elemental semiconductors
61.80.Jh Ion radiation effects
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
78.70.Dm X-ray absorption spectra
61.72.Cc Kinetics of defect formation and annealing
81.40.Gh Other heat and thermomechanical treatments
71.55.Cn Elemental semiconductors

Dielectric properties of lithium triborate single crystals

Ji Won Kim, Choon Sup Yoon, and H. G. Gallagher

Appl. Phys. Lett. 71, 3212 (1997); http://dx.doi.org/10.1063/1.120293 (3 pages) | Cited 4 times

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From the impedance analysis, we report the dielectric constants of lithium triborate single crystals for the three principal axes in the frequency range of 100 Hz–1 MHz and in the temperature range of 303–773 K. The observed highly anisotropic behavior of dielectric dispersions is mainly related to the anisotropy of the activation energy for Li+ ion hopping, which is constituted by the B3O7 channel framework lain along the c axis. © 1997 American Institute of Physics.
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77.22.Ch Permittivity (dielectric function)
66.30.H- Self-diffusion and ionic conduction in nonmetals

Multimodal impurity redistribution and nanocluster formation in Ge implanted silicon dioxide films

J. von Borany, R. Grötzschel, K. H. Heinig, A. Markwitz, W. Matz, B. Schmidt, and W. Skorupa

Appl. Phys. Lett. 71, 3215 (1997); http://dx.doi.org/10.1063/1.120294 (3 pages) | Cited 49 times

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The depth distribution of Ge implanted into thermally grown SiO2 films has been studied after annealing using transmission electron microscopy, Rutherford backscattering spectrometry, and x-ray diffraction. At annealing temperatures above 900 °C a significant redistribution of the as-implanted Ge profile was found. Crystalline Ge nanoclusters embedded in the SiO2 matrix are formed within a cluster band with well defined boundaries. The evolution of nanoclusters can be explained qualitatively by a model based on nucleation, growth and Ostwald ripening of Ge precipitates. Besides, chemical and interface reactions lead to the formation of additional Ge peaks near the surface and at the Si/SiO2 interface. © 1997 American Institute of Physics.
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61.72.up Other materials
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
85.40.Ry Impurity doping, diffusion and ion implantation technology
61.72.S- Impurities in crystals
61.46.-w Structure of nanoscale materials

An improved analysis for the determination of trap levels in silicon from laser microwave photoconductive decay measurements

C. H. Ling and Z. Y. Cheng

Appl. Phys. Lett. 71, 3218 (1997); http://dx.doi.org/10.1063/1.120295 (3 pages) | Cited 2 times

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Dominant trap energy levels in silicon are extracted from the temperature dependence of minority carrier recombination lifetime, observed through laser microwave photoconductive decay. A small correction is made to the Arrhenius plot by incorporating the weakly temperature-dependent term in the recombination lifetime expression, hitherto ignored. The new extraction technique is simple to implement and the results are in good agreement with published data. © 1997 American Institute of Physics.
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72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
72.40.+w Photoconduction and photovoltaic effects
72.80.Cw Elemental semiconductors
72.30.+q High-frequency effects; plasma effects

Improvement of leakage current characteristics of Ba0.5Sr0.5TiO3 films by N2O plasma surface treatment

Hag-Ju Cho, Sejun Oh, Chang Seok Kang, Cheol Seong Hwang, Byoung Taek Lee, Ki Hoon Lee, Hideki Horii, Sang In Lee, and Moon Yong Lee

Appl. Phys. Lett. 71, 3221 (1997); http://dx.doi.org/10.1063/1.120296 (3 pages) | Cited 18 times

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The effects of plasma surface treatment, using N2O gas, of Ba0.5Sr0.5TiO3 (BST) film on the leakage current characteristic of a Pt/BST/Pt capacitor were investigated. As a result of exposure of BST film to the plasma, the leakage current density of the BST capacitor decreased by two orders of magnitude in the high voltage region, and higher onset voltage of an abrupt increase in leakage current was observed. The improvement of leakage properties of BST films can be attributed to the elimination of the bulged curve in the leakage current characteristics. Thermal desorption spectroscopy showed that the elimination was closely related to the reduction of carbon content in the BST film. © 1997 American Institute of Physics.  
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73.40.Rw Metal-insulator-metal structures
77.55.-g Dielectric thin films
84.32.Tt Capacitors
73.61.Ng Insulators
68.03.Fg Evaporation and condensation of liquids
68.43.Mn Adsorption kinetics
81.65.-b Surface treatments

Evidence of compensating centers as origin of yellow luminescence in GaN

E. F. Schubert, I. D. Goepfert, and J. M. Redwing

Appl. Phys. Lett. 71, 3224 (1997); http://dx.doi.org/10.1063/1.120297 (3 pages) | Cited 48 times

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The dependence of the near-band edge and the yellow luminescence in n-type GaN grown by organometallic vapor-phase epitaxy is investigated as a function of doping concentration. The band edge and yellow luminescence intensity increase as the doping concentration is increased. However, the band-edge-to-yellow luminescence ratio does not change significantly as the doping concentration is increased by two orders of magnitude. A theoretical model based on rate equations is developed for the band-edge-to-yellow intensity ratio. Analysis of the experimental data in terms of the model reveals that the concentration of the level causing the yellow luminescence increases linearly with doping concentration. This dependence shows that the yellow luminescence is due to a compensating center. © 1997 American Institute of Physics.
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78.66.Fd III-V semiconductors
78.55.Cr III-V semiconductors
71.55.Eq III-V semiconductors

Observation of strain relaxation phenomena in buried and nonburied III–V surface gratings through high resolution x-ray diffraction

L. Leprince, G. T. Baumbach, A. Talneau, M. Gailhanou, and J. Schneck

Appl. Phys. Lett. 71, 3227 (1997); http://dx.doi.org/10.1063/1.120298 (3 pages) | Cited 12 times

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We present high-resolution x-ray diffraction studies describing the evolution of the strain relaxation phenomena in a strained InGaAsP surface grating resulting from burying in InP. We have compared reciprocal space maps of symmetrical and asymmetrical reflections from free-strain gratings, strained surface gratings, and strained buried gratings. After burying, modifications in the coherently and diffusely scattered intensity have been observed indicating the counteraction of the embedding material to the laterally nonuniform strain relaxation, which occurs in free-surface (nonburied) strained grating. © 1997 American Institute of Physics.
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68.35.Gy Mechanical properties; surface strains
68.60.Bs Mechanical and acoustical properties
42.79.Dj Gratings

Ultimate limit for defect generation in ultra-thin silicon dioxide

D. J. DiMaria and J. H. Stathis

Appl. Phys. Lett. 71, 3230 (1997); http://dx.doi.org/10.1063/1.120299 (3 pages) | Cited 54 times

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Experimental and theoretical investigations are reported for defect generation by electrical stress in silicon dioxide and for the critical number of defects necessary to trigger destructive breakdown. Experimental evidence is presented showing that the critical number of defects reaches a limit when the oxide thickness is reduced below 2.7 nm. Percolation calculations are shown to be consistent with this oxide thickness limit representing the “effective size” of one defect spanning the oxide, connecting anode and cathode together. Also, these calculations show that not all of the defects are capable of triggering a destructive breakdown event. © 1997 American Institute of Physics.
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73.61.Ng Insulators
77.22.Jp Dielectric breakdown and space-charge effects
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
77.55.-g Dielectric thin films
61.72.-y Defects and impurities in crystals; microstructure
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)

Mechanism of organization of three-dimensional islands in SiGe/Si multilayers

E. Mateeva, P. Sutter, J. C. Bean, and M. G. Lagally

Appl. Phys. Lett. 71, 3233 (1997); http://dx.doi.org/10.1063/1.120300 (3 pages) | Cited 79 times

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The organization of coherent three-dimensional islands during the growth of SiGe/Si multilayers on Si(100) was investigated with cross-sectional transmission electron microscopy. Merging of islands of different initial size is found to be the dominant mechanism leading to a uniform size distribution. Upon overgrowth with Si, we observe a change of the shape of the islands from the {105}-faceted “hut” to a boxlike shape bounded on top by a (100) facet. © 1997 American Institute of Physics.
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68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties
81.05.Cy Elemental semiconductors
81.05.Hd Other semiconductors
68.55.-a Thin film structure and morphology

1/f dielectric polarization noise in silicon p-n junctions

Makoto Akiba

Appl. Phys. Lett. 71, 3236 (1997); http://dx.doi.org/10.1063/1.120301 (3 pages) | Cited 5 times

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Dielectric polarization noise in silicon p-n junctions was measured at low leakage current, less than 1×10−17 A, and at temperatures between 110 and 200 K. The power spectra of the noise voltages exhibit 1/f characteristics, where f is the frequency. The dielectric loss of the p-n junctions, which was derived from the 1/f noise by using the fluctuation-dissipation theorem, is proportional to the temperature, and is almost independent of the characteristics of the p-n junctions. © 1997 American Institute of Physics.
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73.40.Lq Other semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
77.22.Ej Polarization and depolarization
72.70.+m Noise processes and phenomena
73.61.Cw Elemental semiconductors

Conduction band spectra in self-assembled InAs/GaAs dots: A comparison of effective mass and an eight-band approach

Hongtao Jiang and Jasprit Singh

Appl. Phys. Lett. 71, 3239 (1997); http://dx.doi.org/10.1063/1.120302 (3 pages) | Cited 23 times

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Strained epitaxy has been shown to produce high quality InAs/GaAs quantum dot structures by single step epitaxy. While effective mass-based approaches have been used for quantum structures, the nature of the strain and quantum confinement in self-assembled dots is such that this is not a good approximation. In this letter, we use an eight-band k⋅p formalism to find the electronic spectra in InAs/GaAs dots. The eight-band model shows that, in agreement with experiments, there are indeed several bound states in the conduction band well. Our results show that the simpler effective mass approaches cannot be used to quantitatively examine the physics of intersubband devices based on self-assembled quantum dots. Intersubband optical matrix elements and Coulomb blockade energy are also calculated in this letter. © 1997 American Institute of Physics.
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73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems
73.61.Ey III-V semiconductors
85.35.Be Quantum well devices (quantum dots, quantum wires, etc.)
73.40.Kp III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
73.23.Hk Coulomb blockade; single-electron tunneling
73.50.Gr Charge carriers: generation, recombination, lifetime, trapping, mean free paths

Polarization of an organic monomeric glass

T. E. Karis, R. J. Twieg, P. M. Lundquist, and J. F. Castro

Appl. Phys. Lett. 71, 3242 (1997); http://dx.doi.org/10.1063/1.120303 (3 pages)

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A methylene dihydropyridine with a high ground-state dipole moment was investigated to explore the possibility of using it to form an organic monomeric glass “electret” film. Measurements were done in a specially designed test cell. An electric field was applied to a 100-μm-thick film of dihydropyridine while cooling from a melt. The cell potential was recorded as a function of time to study the homocharge and polarization relaxations. The homocharge relaxation time was ≈ 900 s. The polarization relaxation time was ≈ 2×105 s in the vicinity of the glass transition temperature. The polarization is linear over a wide range of electric field strength. © 1997 American Institute of Physics.
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77.22.Ej Polarization and depolarization
77.22.Gm Dielectric loss and relaxation
77.84.Jd Polymers; organic compounds
64.70.P- Glass transitions of specific systems
64.70.Q- Theory and modeling of the glass transition

Polarization threshold switches based on ordered GaInP

E. Greger, P. Riel, M. Moser, T. Kippenberg, P. Kiesel, and G. H. Döhler

Appl. Phys. Lett. 71, 3245 (1997); http://dx.doi.org/10.1063/1.120304 (3 pages) | Cited 20 times

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We report on optoelectronic switching devices with high photoconductive gain which are sensitive to the polarization direction of the optical input. Due to the large polarization anisotropy of the absorption coefficient of ordered GaInP, an electrical output can be switched “on” and “off” by rotating the linear polarization of the input light. Depending on the external adjustment of the working point, the structure can operate as a polarization threshold switch or a polarization detector, respectively. First results exhibit a switching contrast of 25 dB and a contrast of the detector signal of 7 dB between two perpendicularly polarized incident light beams, respectively. © 1997 American Institute of Physics.
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85.60.-q Optoelectronic devices
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
72.60.+g Mixed conductivity and conductivity transitions
72.40.+w Photoconduction and photovoltaic effects
07.60.Fs Polarimeters and ellipsometers
85.60.Gz Photodetectors (including infrared and CCD detectors)

Carbon-doped GaInP/GaAs heterojunction bipolar transistors grown by metalorganic chemical vapor deposition using nitrogen as the carrier gas

C. C. Hsu, Y. F. Yang, H. J. Ou, E. S. Yang, and H. B. Lo

Appl. Phys. Lett. 71, 3248 (1997); http://dx.doi.org/10.1063/1.120305 (3 pages) | Cited 8 times

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The use of nitrogen as the carrier gas in metalorganic chemical vapor deposition (MOCVD) for the growth of carbon-doped GaInP/GaAs heterojunction bipolar transistors (HBTs) is reported. The material quality grown using a nitrogen carrier gas is the same as that of using a hydrogen carrier gas. High carbon doping and hole concentrations of 3×1020 and 2×1020 cm−3 in GaAs were obtained. The fabricated HBTs showed very good DC and RF performances indicating that nitrogen can be a promising carrier gas for MOCVD growth. © 1997 American Institute of Physics.
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85.30.Pq Bipolar transistors
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
81.05.Ea III-V semiconductors
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
61.72.uj III-V and II-VI semiconductors

High performance InAs/Ga1-xInxSb superlattice infrared photodiodes

F. Fuchs, U. Weimer, W. Pletschen, J. Schmitz, E. Ahlswede, M. Walther, J. Wagner, and P. Koidl

Appl. Phys. Lett. 71, 3251 (1997); http://dx.doi.org/10.1063/1.120551 (3 pages) | Cited 104 times

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The optical and electrical properties of infrared photodiodes diodes based on InAs/(GaIn)Sb superlattices grown by molecular beam epitaxy were investigated. The diodes, with a cut-off wavelength around 8 μm show a current responsivity of 2 A/W. By proper adjustment of the p-doping level above the n-background concentration the depletion width exceeds a critical size of about 60 nm, leading to the suppression of band-to-band tunneling currents. Above that critical width the dynamic impedance R0A at 77 K reaches values above 1 kΩ cm2 leading to a Johnson-noise-limited detectivity in excess of 1×1012 cm√Hz/W. © 1997 American Institute of Physics.
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85.60.Dw Photodiodes; phototransistors; photoresistors
85.60.Gz Photodetectors (including infrared and CCD detectors)

Selective positioning of InAs self-organized quantum dots on sub-250 nm GaAs facets

R. Tsui, R. Zhang, K. Shiralagi, and H. Goronkin

Appl. Phys. Lett. 71, 3254 (1997); http://dx.doi.org/10.1063/1.120306 (3 pages) | Cited 19 times

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We have selectively grown GaAs mesas with (100) top facets that range from several μm to less than 250 nm in width on an oxide-patterned GaAs substrate, and InAs self-organized quantum dots (SOQDs) on top of the facets. For a given amount of InAs deposited, the dot density varies with the facet width, and is higher than the density on a planar, nonpatterned substrate. The SOQDs also tend to form at the facet edges. These observations are indicative of a strong surface diffusion effect of In-containing species adsorbed on the various crystalline facets of the GaAs mesas. © 1997 American Institute of Physics.
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81.05.Ea III-V semiconductors
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
68.35.B- Structure of clean surfaces (and surface reconstruction)
68.35.Fx Diffusion; interface formation
68.08.-p Liquid-solid interfaces
68.43.-h Chemisorption/physisorption: adsorbates on surfaces

Annealing effects in ZnSe/GaAs heterostructure grown by molecular beam epitaxy

J. Y. Leem, J. S. Son, C. R. Lee, C. S. Kim, Y. K. Cho, Hwack J. Lee, S. K. Noh, and I. H. Bae

Appl. Phys. Lett. 71, 3257 (1997); http://dx.doi.org/10.1063/1.120307 (3 pages) | Cited 3 times

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In the ZnSe/GaAs heterostructure, the problems of interdiffusion and thermal stability are very crucial. We have investigated the effects of annealing on ZnSe grown on GaAs by photoluminescence and double-crystal x-ray measurement. In order to investigate annealing effects of the ZnSe/GaAs heterostructure, we used 1.0-μm-thick and 0.2-μm-thick samples. Samples were annealed in the temperature range of 200–500 °C in an N2 ambient for 3 min using a face-to-face configuration with ZnSe epitaxial layer as a cap layer. In the annealing temperature above 450 °C, new emission peaks appeared in the range of 2.62–2.72 eV. The biaxial compressive strain due to lattice mismatch at the growth temperature is mostly relaxed at 400 °C, and the epilayer annealed at 500 °C has a biaxial tensile strain. © 1997 American Institute of Physics.
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61.72.Cc Kinetics of defect formation and annealing
68.55.-a Thin film structure and morphology
68.60.Dv Thermal stability; thermal effects
78.66.Fd III-V semiconductors
68.35.Fx Diffusion; interface formation
78.55.Cr III-V semiconductors

Short-wavelength photoluminescence and electroluminescence in Ga(Al)P/GaP staggered type II quantum wells

M. Gerhold, K. Kamath, and P. Bhattacharya

Appl. Phys. Lett. 71, 3260 (1997); http://dx.doi.org/10.1063/1.120320 (3 pages)

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Photoluminescence spectra of tailored Ga(A1)P/GaP quantum well heterostructures exhibit strong short-wavelength peaks at 363, 560, and 600−700 nm. The peak at 560 nm seems to originate from a no-phonon transition. All the transitions are observed up to 200 K. Light emitting diodes made with the same heterostructure predominently emit 560 nm light (green) with a background of 700 nm (red) at room temperature under cw operation. © 1997 American Institute of Physics.
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85.35.Be Quantum well devices (quantum dots, quantum wires, etc.)
78.66.Fd III-V semiconductors
78.55.Cr III-V semiconductors
78.60.Fi Electroluminescence
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems
73.61.Ey III-V semiconductors
85.60.Jb Light-emitting devices

The analysis of one-dimensional conductance quantization in V∣amorphous-V2O5∣V thin film devices

Eui-Jung Yun, Jwa-Yeon Kim, and R. M. Walser

Appl. Phys. Lett. 71, 3263 (1997); http://dx.doi.org/10.1063/1.120321 (3 pages)

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We report experiments to determine whether the room temperature one-dimensional conductance quantization (1DCQ) is present at the V∣amorphous-V2O5 interphase in as-deposited V∣amorphous-V2O5∣V devices, or nucleated by a critical event at the threshold voltage VT where ballistic transport was initiated. The fit of the material parameters (barrier width, barrier height, dielectric constant) to the I–V data, the oxide thickness independence of resistance, and variations in the device capacitance with junction area and oxide thickness, suggest that the 1DCQ is associated with the formation of a low dimensional conducting filament through a ∼ 20 Å-thick VOx interphase layer. The data show that VT is unusually low ( ∼ 8 kT/q where T = 300 °K), nearly independent of device area and oxide thickness, and has only a small ( ∼ kT/q) statistical variation from device to device. These data suggest that the interphase transition at the voltage VT is reversible, but, were inconclusive in determining whether the interphase transition occurs at a critical field or is induced by thermal effects. The threshold voltage VT also decreases as (T−Tc)n (n ∼ 0.5) going to zero near Tc ≈ 60 °C. An analysis of the data suggests that the interphase transition most likely occurs by a critical event associated with an inelastic transfer of energy ∼ kTc/q at the V∣a-V2O5 interphase. © 1997 American Institute of Physics.
Show PACS
73.40.Rw Metal-insulator-metal structures
73.23.Ad Ballistic transport
77.22.Ch Permittivity (dielectric function)
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