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9 Oct 2006

Volume 89, Issue 15, Articles (15xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 89, 151920 (2006); http://dx.doi.org/10.1063/1.2360906 (3 pages)

Aycan Yurtsever, Matthew Weyland, and David A. Muller
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Investigation of effective mass of carriers in Bi2Te3̸Sb2Te3 superlattices via electronic structure studies on its component crystals

Guofeng Wang and Tahir Cagin

Appl. Phys. Lett. 89, 152101 (2006); http://dx.doi.org/10.1063/1.2360191 (3 pages) | Cited 7 times

Online Publication Date: 9 October 2006

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The electronic structures of Bi2Te3 and Sb2Te3 were computed and related to the thermoelectric properties of Bi2Te3̸Sb2Te3 superlattices. The authors found that the similarity of the electronic structure of the two materials permits the Bi2Te3̸Sb2Te3 superlattices inherit high band edge degeneracy, and thus have high electrical conductivity. From the calculated effective mass along the superlattice growth direction, we infer that presence of more Sb2Te3 than Bi2Te3 in the superlattice leads to a smaller effective mass and enhanced carrier mobility. Furthermore, our results suggest that external tensile strain parallel to the interface may further improve the thermoelectric performance of the Bi2Te3̸Sb2Te3 superlattices.
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73.21.Cd Superlattices
73.63.-b Electronic transport in nanoscale materials and structures
73.20.At Surface states, band structure, electron density of states
72.20.Pa Thermoelectric and thermomagnetic effects
72.20.Fr Low-field transport and mobility; piezoresistance
71.18.+y Fermi surface: calculations and measurements; effective mass, g factor

Electrostatic force microscopy as a tool to estimate the number of active potential barriers in dense non-Ohmic polycrystalline SnO2 devices

J. S. Vasconcelos, N. S. L. S. Vasconcelos, M. O. Orlandi, P. R. Bueno, J. A. Varela, E. Longo, C. M. Barrado, and E. R. Leite

Appl. Phys. Lett. 89, 152102 (2006); http://dx.doi.org/10.1063/1.2354483 (3 pages) | Cited 11 times

Online Publication Date: 9 October 2006

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In the present work, electroactive grain boundaries of highly dense metal oxide SnO2-based polycrystalline varistors were determined by electrostatic force microscopy (EFM). The EFM technique was applied to identify electroactive grain boundaries and thus estimate the amount of active grain boundary, which, in the metal oxide SnO2-based varistor, was calculated at around 85%, i.e., much higher than that found in traditional metal oxide ZnO-based varistors. The mean potential barrier height value obtained from the EFM analysis was in complete agreement with the values calculated from the C-V measurements, together with a complex capacitance plane analysis that validates the methodology proposed here.
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84.32.Ff Conductors, resistors (including thermistors, varistors, and photoresistors)

Inherent density of point defects in thermal tensile strained (100)Si/SiO2 entities probed by electron spin resonance

A. Stesmans, P. Somers, V. V. Afanas’ev, C. Claeys, and E. Simoen

Appl. Phys. Lett. 89, 152103 (2006); http://dx.doi.org/10.1063/1.2339033 (3 pages) | Cited 3 times

Online Publication Date: 9 October 2006

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An electron spin resonance analysis has been carried out of the intrinsic point defects in (100)Si/SiO2 entities thermally grown at 800 °C on biaxial tensile strained Si (s-Si). As compared to coprocessed standard (100)Si/SiO2, a significant reduction (>50%) is observed in the inherent density of the trivalent Pb-type interface defects (Pb0,Pb1). With the Pb0’s established as detrimental fast interface traps, this result may adduce one more reason for the observed enhancement of device channel carrier mobility with increasing Si substrate tensile strain as well as reduction in 1/f noise. The s-Si/SiO2 interface exhibits a generally superior device grade quality.
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61.72.J- Point defects and defect clusters
81.40.Lm Deformation, plasticity, and creep
62.20.F- Deformation and plasticity
76.30.Da Ions and impurities: general
68.35.Ct Interface structure and roughness
73.20.At Surface states, band structure, electron density of states

Time resolved photocurrent, microwave spectrum, and multiple high-field domains in dc-biased GaAs

I. Kašalynas and L. Subačius

Appl. Phys. Lett. 89, 152104 (2006); http://dx.doi.org/10.1063/1.2360254 (3 pages) | Cited 1 time

Online Publication Date: 9 October 2006

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The authors present an experimental study of the time resolved photocurrent and its Fourier spectrum in dc-biased semi-insulating GaAs under multiple high-field domains photoexcitation. It is observed that nanosecond duration light interference pattern induces subnanosecond instabilities on the falling slope of the photocurrent pulse only when the external dc field reaches a threshold field value, i.e., when a transient multi-domain structure drifting through the spatially modulated semiconductor is generated. The signal spectrum in the gigahertz range is broad but, if system parameters are set properly, the spectrum becomes stable and concentrated at a single frequency proportional to the spatial period of the light interference pattern and the drift velocity of the domains.
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72.40.+w Photoconduction and photovoltaic effects
78.47.-p Spectroscopy of solid state dynamics
78.70.Gq Microwave and radio-frequency interactions

Strain evolution in GaN layers grown on high-temperature AlN interlayers

J. F. Wang, D. Z. Yao, J. Chen, J. J. Zhu, D. G. Zhao, D. S. Jiang, H. Yang, and J. W. Liang

Appl. Phys. Lett. 89, 152105 (2006); http://dx.doi.org/10.1063/1.2360900 (3 pages) | Cited 21 times

Online Publication Date: 9 October 2006

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The strain evolution of the GaN layer grown on a high-temperature AlN interlayer with GaN template by metal organic chemical vapor deposition is investigated. It is found that the layer is initially under compressive strain and then gradually relaxes and transforms to under tensile strain with increasing film thickness. The result of the in situ stress analysis is confirmed by x-ray diffraction measurements. Transmission electron microscopy analysis shows that the inclination of edge and mixed threading dislocations rather than the reduction of dislocation density mainly accounts for such a strain evolution.
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68.60.Bs Mechanical and acoustical properties
68.55.A- Nucleation and growth
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
81.15.Kk Vapor phase epitaxy; growth from vapor phase
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.

Band structure of the epitaxial Fe/MgO/GaAs(001) tunnel junction studied by x-ray and ultraviolet photoelectron spectroscopies

Y. Lu, J. C. Le Breton, P. Turban, B. Lépine, P. Schieffer, and G. Jézéquel

Appl. Phys. Lett. 89, 152106 (2006); http://dx.doi.org/10.1063/1.2361273 (3 pages) | Cited 14 times

Online Publication Date: 9 October 2006

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The electronic band structure in the epitaxial Fe/MgO/GaAs(001) tunnel junction has been studied by x-ray and ultraviolet photoelectron spectroscopy measurements. The Schottky barrier height (SBH) of Fe on MgO/GaAs heterostructure is determined to be 3.3±0.1 eV, which sets the Fe Fermi level at about 0.3 eV above the GaAs valence band maximum. This SBH is also exactly the same as that measured from Fe on MgO monocrystal. After Fe deposition, no band bending change is observed in MgO and GaAs underlayers. On the contrary, Au and Al depositions led to clear variation of the band bending in both MgO and GaAs layers. This effect is analyzed as a fingerprint of defect states at the MgO/GaAs interface.
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73.20.At Surface states, band structure, electron density of states
78.70.Dm X-ray absorption spectra
79.60.Bm Clean metal, semiconductor, and insulator surfaces
82.80.Pv Electron spectroscopy (X-ray photoelectron (XPS), Auger electron spectroscopy (AES), etc.)
73.30.+y Surface double layers, Schottky barriers, and work functions
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)

Ultraviolet photoluminescence from Gd-implanted AlN epilayers

J. M. Zavada, N. Nepal, J. Y. Lin, H. X. Jiang, E. Brown, U. Hömmerich, J. Hite, G. T. Thaler, C. R. Abernathy, S. J. Pearton, and R. Gwilliam

Appl. Phys. Lett. 89, 152107 (2006); http://dx.doi.org/10.1063/1.2357552 (3 pages) | Cited 19 times

Online Publication Date: 10 October 2006

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Deep ultraviolet emission from gadolinium (Gd)-implanted AlN thin films has been observed using photoluminescence (PL) spectroscopy. The AlN epilayers were ion implanted with Gd to a total dose of ∼ 6×1014 cm−2. Using the output at 197 nm from a quadrupled Ti:sapphire laser, narrow PL emission was observed at 318 nm, characteristic of the trivalent Gd ion. A broader emission band, also centered at 318 nm, was measured with excitation at 263 nm. The PL emission intensity decreased by less than a factor of 3 over the sample temperature range of 10–300 K and decay transients were of the order of nanoseconds.
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81.05.Ea III-V semiconductors
78.55.Cr III-V semiconductors
78.66.Fd III-V semiconductors
61.72.uj III-V and II-VI semiconductors
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
61.80.Jh Ion radiation effects

I-V characteristics of Au/Ni Schottky diodes on GaN with SiNx nanonetwork

Jinqiao Xie, Yi Fu, Xianfeng Ni, Serguei Chevtchenko, and Hadis Morkoç

Appl. Phys. Lett. 89, 152108 (2006); http://dx.doi.org/10.1063/1.2359294 (3 pages) | Cited 5 times

Online Publication Date: 10 October 2006

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Room temperature and temperature dependent current-voltage characteristics of Ni/Au Schottky diodes fabricated on undoped GaN prepared with and without in situ SiNx nanonetwork by metal organic chemical vapor deposition have been studied. The features of the Schottky diodes depend strongly on the SiNx deposition conditions, namely, its thickness. Reduction in the point and line defect densities caused the Schottky barrier height to increase to 1.13 eV for 5 min SiNx deposition time as compared to 0.78 eV without SiNx nanonetwork. Similarly, the breakdown voltage also improved from 76 V for the reference to 250 V when SiNx nanonetwork was used. With optimized SiNx nanonetwork, full width at half maximum values of (0002) and (10math2) x-ray rocking curves improved to 217 and 211 arc sec, respectively, for a 5.5 μm thick layer, as compared to 252 and 405 arc sec for a reference sample of the same thickness, which are comparable to literature values. The photoluminescence linewidth also reduced to 2.5 meV at 15 K with free excitons A and B clearly resolvable.
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85.30.Kk Junction diodes

Dynamics of excitons and Coulomb beats in a quantum dot molecule

Marcos H. Degani, Gil A. Farias, and Paulo F. Farinas

Appl. Phys. Lett. 89, 152109 (2006); http://dx.doi.org/10.1063/1.2359574 (3 pages) | Cited 6 times

Online Publication Date: 10 October 2006

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The authors present results for the energy spectrum and the dynamical behavior of excitons in an asymmetric quantum dot molecule. Two main resonances are found by using parameters from GaAs-based systems. Excitonic and binding energies are calculated as functions of an external electric field. They fully explore the dynamics of the exciton, showing the time evolution of both the electron and hole components. The effect of the Coulomb interaction is found to be quite dramatic and responsible for considerably large resonance fields as well as for some underlying beatings found in the main oscillation pattern.
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73.21.La Quantum dots
71.35.-y Excitons and related phenomena
71.15.Nc Total energy and cohesive energy calculations

Rubrene single crystal field-effect transistor with epitaxial BaTiO3 high-k gate insulator

Nobuya Hiroshiba, Ryotaro Kumashiro, Katsumi Tanigaki, Taishi Takenobu, Yoshihiro Iwasa, Kenta Kotani, Iwao Kawayama, and Masayoshi Tonouchi

Appl. Phys. Lett. 89, 152110 (2006); http://dx.doi.org/10.1063/1.2360207 (3 pages) | Cited 4 times

Online Publication Date: 11 October 2006

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High quality BaTiO3 thin-film epitaxially grown on a Nb-doped SrTiO3 (BTO/Nb-STO) substrate by a laser ablation technique is employed as a high-k gate insulator for a field-effect transistor of a rubrene single crystal in order to search for the possibility of high carrier accumulation. The high dielectric constant ϵ of 280 esu for the prepared BaTiO3 thin-film accumulates 0.1 holes/rubrene-molecule, which is 2.5 times as high as the maximum carrier number of 0.04 holes/rubrene-molecule attained in the case of SiO2. This is the highest carrier number so far obtained in organic field-effect transistors (FETs). Other important parameters of rubrene single crystal FETs on BTO/Nb-STO are described in comparison with those on SiO2/doped-Si.
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85.30.Tv Field effect devices
61.80.Ba Ultraviolet, visible, and infrared radiation effects (including laser radiation)

Nonvolatile memory device based on the switching by the all-organic charge transfer complex

Jin-Sik Choi, Ji-Ho Kim, Song-Ho Kim, and Dong Hack Suh

Appl. Phys. Lett. 89, 152111 (2006); http://dx.doi.org/10.1063/1.2360220 (3 pages) | Cited 13 times

Online Publication Date: 11 October 2006

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The authors have investigated the nonvolatile memory device by the amorphous charge transfer complex of 2, 4, 7-trinitro-9-fluorenone and poly(N-vinylcarbazole) as a spin-coated active layer. The reversible switching can be controlled by the external electric field and the on/off ratio is more than three orders at 1 V. The device operation might be interpreted as the generation and the extinction of charged carriers in the active layer through the results of the capacitance and the impedance at each state.
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84.30.Sk Pulse and digital circuits

Homoepitaxial growth and electrical characterization of iron-doped semi-insulating 4H-SiC epilayer

Ho Keun Song, Sun Young Kwon, Han Seok Seo, Jeong Hyun Moon, Jeong Hyuk Yim, Jong Ho Lee, Hyeong Joon Kim, and Jae Kyeong Jeong

Appl. Phys. Lett. 89, 152112 (2006); http://dx.doi.org/10.1063/1.2354485 (3 pages) | Cited 5 times

Online Publication Date: 11 October 2006

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The authors attempted to grow a semi-insulating silicon carbide (SiC) epitaxial layer by in situ iron doping. The homoepitaxial growth of the iron-doped 4H-SiC layer was performed by metal-organic chemical vapor deposition using the organo-silicon precursor bis(trimethylsilylmethane) (C7H20Si2) and the metal-organic precursor t-butylferrocene (C14H17Fe). For the measurement of the resistivity of the iron-doped 4H-SiC epilayers, the authors used the on resistance of Schottky barrier diode. Based on the measurement of the on resistance, it is shown that the free carrier concentration was decreased with increasing partial pressure of t-butylferrocene. The resistivity of the iron-doped 4H-SiC epilayer was about 108 Ω cm.
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81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
61.72.up Other materials
73.61.Le Other inorganic semiconductors
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.

Enhancement of magnetic properties in (Ga,Mn)N nanowires due to N2 plasma treatment

Jeong Min Baik, Yoon Shon, Tae Won Kang, and Jong-Lam Lee

Appl. Phys. Lett. 89, 152113 (2006); http://dx.doi.org/10.1063/1.2360890 (3 pages) | Cited 2 times

Online Publication Date: 11 October 2006

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The local structure of Mn impurities in ferromagnetic (Ga,Mn)N nanowires was investigated using extended x-ray absorption fine structure (EXAFS). By N2 plasma treatment, the nitrogen concentration increased and the ferromagnetic signal also increased. The EXAFS results showed that the Mn concentration occupying Ga sites increased and interstitially doped Mn atoms significantly decreased due to the plasma treatment. As a result, the N vacancies reduced and crystalline quality improved, resulting in the enhancement of ferromagnetic properties.
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75.75.-c Magnetic properties of nanostructures
75.50.Dd Nonmetallic ferromagnetic materials
75.50.Pp Magnetic semiconductors
68.65.La Quantum wires (patterned in quantum wells)
78.70.Dm X-ray absorption spectra
61.72.J- Point defects and defect clusters

Influence of surface adsorption in improving ultrashallow junction formation

Ramakrishnan Vaidyanathan, Edmund G. Seebauer, Houda Graoui, and Majeed A. Foad

Appl. Phys. Lett. 89, 152114 (2006); http://dx.doi.org/10.1063/1.2360917 (3 pages) | Cited 5 times

Online Publication Date: 11 October 2006

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The continual downscaling of silicon devices for integrated circuits requires the formation of transistor (p-n) junctions that are progressively shallower yet incorporate increasing levels of electrically active dopant. In the case of implanted arsenic, the authors show that both goals can be accomplished simultaneously and controllably through the adsorption of small amounts of atomic nitrogen on the Si(100) surface.
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68.47.Fg Semiconductor surfaces
68.43.Mn Adsorption kinetics
61.72.uf Ge and Si

Band offset measurements of ZnO/6H-SiC heterostructure system

Ya. I. Alivov, B. Xiao, Q. Fan, H. Morkoç, and D. Johnstone

Appl. Phys. Lett. 89, 152115 (2006); http://dx.doi.org/10.1063/1.2360924 (3 pages) | Cited 13 times

Online Publication Date: 11 October 2006

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The conduction band offset of n-ZnO/n-6H-SiC heterostructures fabricated by rf-sputtered ZnO on commercial n-type 6H-SiC substrates has been measured by a variety of methods. Temperature dependent current-voltage characteristic, photocapacitance, and deep level transient spectroscopy measurements showed the conduction band offsets to be 1.25, 1.1, and 1.22 eV, respectively.
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73.21.Ac Multilayers
73.20.At Surface states, band structure, electron density of states
73.40.Kp III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
71.55.Gs II-VI semiconductors
72.40.+w Photoconduction and photovoltaic effects

Colossal electroresistance and current induced switching in ferromagnetic insulating state of La0.82Ca0.18MnO3

Himanshu Jain, A. K. Raychaudhuri, Ya. M. Mukovskii, and D. Shulyatev

Appl. Phys. Lett. 89, 152116 (2006); http://dx.doi.org/10.1063/1.2361168 (3 pages) | Cited 20 times

Online Publication Date: 11 October 2006

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Colossal electroresistance and current induced resistivity switching have been measured in the ferromagnetic insulating (FMI) state of single crystal manganite La0.82Ca0.18MnO3. The sample has a Curie transition temperature TC = 165 K and the FMI state is realized for temperatures T<100 K. The electroresistance (ER), arising from a strong nonlinear resistivity, attains a large value ( ≈ 100%) in the FMI state. However, this is accompanied by a collapse of the magnetoresistance (MR) to a small value even in magnetic field (H) of 10 T. This demonstrates that the mechanisms that give rise to ER and MR are effectively decoupled.
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75.47.Gk Colossal magnetoresistance
75.47.Lx Magnetic oxides
75.30.Kz Magnetic phase boundaries (including classical and quantum magnetic transitions, metamagnetism, etc.)
75.50.Dd Nonmetallic ferromagnetic materials

Fabrication of dislocation-free tensile strained Si thin films using controllably oxidized porous Si substrates

Jeehwan Kim and Ya-Hong Xie

Appl. Phys. Lett. 89, 152117 (2006); http://dx.doi.org/10.1063/1.2360930 (3 pages) | Cited 6 times

Online Publication Date: 12 October 2006

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A method to fabricate strained Si films is reported via the oxidation of a thin Si film on a porous Si substrate. The Si film can be put under tensile stress in a controllable fashion through the expansion of the porous Si upon low temperature oxidation. The thin Si layer on porous Si substrate can be fabricated using a self-limiting anodization of epitaxially grown intrinsic Si on a heavily doped p-type Si substrate. Tensile strain of up to ∼ 1% is observed in 100 nm thick Si films, making it suitable for the various device applications based on strained Si.
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81.05.Cy Elemental semiconductors
68.55.A- Nucleation and growth
81.65.Mq Oxidation
62.20.F- Deformation and plasticity
81.40.Lm Deformation, plasticity, and creep
68.60.Bs Mechanical and acoustical properties

Analysis of trapped quantum degenerate dipolar excitons

Ronen Rapaport, Gang Chen, and Steven Simon

Appl. Phys. Lett. 89, 152118 (2006); http://dx.doi.org/10.1063/1.2361187 (3 pages) | Cited 3 times

Online Publication Date: 12 October 2006

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The dynamics of quantum degenerate two-dimensional dipolar excitons confined in electrostatic traps is analyzed and compared to recent experiments. The model results stress the importance of artificial trapping for achieving and sustaining a quantum degenerate exciton fluid in such systems and suggest that a long-lived, spatially uniform, and highly degenerate exciton system was experimentally produced in those electrostatic traps.
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71.35.Aa Frenkel excitons and self-trapped excitons
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping

Molecular gap and energy level diagram for pentacene adsorbed on filled d-band metal surfaces

Chiara Baldacchini, Carlo Mariani, Maria Grazia Betti, L. Gavioli, M. Fanetti, and M. Sancrotti

Appl. Phys. Lett. 89, 152119 (2006); http://dx.doi.org/10.1063/1.2359573 (3 pages) | Cited 16 times

Online Publication Date: 12 October 2006

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The authors present a combined photoemission and scanning-tunneling spectroscopy study of the filled electronic states, the molecular energy gap, and the energy level diagram of highly ordered arrays of pentacene deposited on the Cu(119) vicinal surface. The states localized at the interface are clearly singled out, comparing the results at different pentacene thicknesses and with gas-phase photoemission data. The molecular gap of 2.35 eV, the hole injection barrier of 1.05 eV, and the electron injection barrier of 1.30 eV determine the energy level diagram of the states localized at the pentacene molecules.
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71.20.Rv Polymers and organic compounds
79.60.Dp Adsorbed layers and thin films
73.20.At Surface states, band structure, electron density of states
68.37.Xy Scanning Auger microscopy, photoelectron microscopy
68.37.Ef Scanning tunneling microscopy (including chemistry induced with STM)

Correlation between optical and electrical properties of Mg-doped AlN epilayers

M. L. Nakarmi, N. Nepal, C. Ugolini, T. M. Altahtamouni, J. Y. Lin, and H. X. Jiang

Appl. Phys. Lett. 89, 152120 (2006); http://dx.doi.org/10.1063/1.2362582 (3 pages) | Cited 17 times

Online Publication Date: 13 October 2006

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Deep UV photoluminescence and Hall-effect measurements were employed to characterize Mg-doped AlN grown by metal organic chemical vapor deposition. A strong correlation between the optical and electrical properties was identified and utilized for material and p-type conductivity optimization. An impurity emission peak at 4.7 eV, attributed to the transition of electrons bound to triply charged nitrogen vacancies to neutral magnesium impurities, was observed in highly resistive epilayers. Improved conductivity was obtained by suppressing the intensity of the 4.7 eV emission line. Mg-doped AlN epilayers with improved conductivities predominantly emit the acceptor-bound exciton transition at 5.94 eV. From the Hall-effect measurements performed at elevated temperatures, the activation energy of Mg in AlN was measured to be about 0.5 eV, which is consistent with the value obtained from previous optical measurements. Energy levels of nitrogen vacancies and Mg acceptors in Mg-doped AlN have been constructed.
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73.61.Ey III-V semiconductors
78.66.Fd III-V semiconductors
73.50.Jt Galvanomagnetic and other magnetotransport effects (including thermomagnetic effects)
78.55.Cr III-V semiconductors
71.55.Eq III-V semiconductors
68.55.A- Nucleation and growth

Hole-transport barrier and band bending at the indium tin oxide/polymer/p-AlGaN interface

Yow-Jon Lin

Appl. Phys. Lett. 89, 152121 (2006); http://dx.doi.org/10.1063/1.2362597 (3 pages)

Online Publication Date: 13 October 2006

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Nonalloyed Ohmic contacts on p-AlGaN were achieved using a thin polymer film [i.e., poly(3,4-ethylenedioxythiophene) (PEDOT) doped with poly(4-styrenesulfonate)] as an interlayer for the electronic modification of indium tin oxide/p-AlGaN contacts. The electronic properties were investigated by current-voltage measurements and x-ray photoelectron spectroscopy (XPS). According to XPS measurements, the authors found a slight reduction in the surface band bending of p-AlGaN following PEDOT coating and the disappearance of the barrier for hole transport at indium tin oxide/PEDOT/p-AlGaN interfaces.
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73.40.-c Electronic transport in interface structures
73.20.At Surface states, band structure, electron density of states
79.60.Jv Interfaces; heterostructures; nanostructures

Logic gates with a single Hall bar heterostructure

R. Sordan, A. Miranda, J. Osmond, D. Chrastina, G. Isella, and H. von Känel

Appl. Phys. Lett. 89, 152122 (2006); http://dx.doi.org/10.1063/1.2362989 (3 pages) | Cited 1 time

Online Publication Date: 13 October 2006

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A four-terminal Hall bar configuration is commonly used in the investigation of transport properties of modulation doped heterostructures. Here it is found that a single Hall bar can act as a multifunction logic gate if a gate electrode is patterned between the voltage probes. Four different logic functions can be obtained depending on the input voltage levels. Operation of all logic gates is demonstrated and merits of such gates with respect to conventional logic gates are discussed.
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84.30.Sk Pulse and digital circuits

Electrical characterization of defects introduced in n-type Ge during indium implantation

F. D. Auret, P. J. Janse van Rensburg, M. Hayes, J. M. Nel, W. E. Meyer, S. Decoster, V. Matias, and A. Vantomme

Appl. Phys. Lett. 89, 152123 (2006); http://dx.doi.org/10.1063/1.2360922 (3 pages) | Cited 8 times

Online Publication Date: 13 October 2006

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The authors have employed deep level transient spectroscopy to investigate the defects introduced in n-type Ge during 160 keV indium (In) ion implantation. Our results show that In implantation introduces three prominent electron traps with energy levels at EC−0.09 eV, EC−0.15 eV, and EC−0.30 eV, respectively. The authors have found that these defects are different from the point defects introduced by electron irradiation but that they do not involve In. Annealing at 600 °C removed all the defects introduced during In implantation but results in a single prominent defect with a level at EC−0.35 eV.
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71.55.Cn Elemental semiconductors
61.72.J- Point defects and defect clusters
61.72.uf Ge and Si
61.80.Fe Electron and positron radiation effects
61.82.Fk Semiconductors
61.72.Cc Kinetics of defect formation and annealing
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