30 Result(s)
within
M. S. Shur
Materials Engineering
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Article
Negative Differential Conductivity in AlGaN/GaN HEMTs: Real Space Charge Transfer from 2D to 3D GaN States?
We report on non-thermal negative differential conductivity (NDC) in AlGaN/GaN HEMTs grown on sapphire substrates by low-pressure MOCVD. The sheet electron density was on the order of few times 1012cm−2 and the H...
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Article
The Influence of Substrate Surface Polarity on Optical Properties of GaN Grown on Single Crystal Bulk AlN
Photoluminescence of the GaN layers grown both on N-face and Al-face bulk AlN is studied under CW and pulsed laser excitation in the temperature range from 8 K to 300 K. We compare localization of excitons, re...
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Article
Growth and Characterization of Deep UV Emitter Structures Grown on Single Crystal Bulk AlN Substrates
We report on high Al-content AlGaN-based deep UV emitter structures grown over single crystal, slightly off c-axis (5.8 degrees) bulk AlN substrates. AlN/AlGaN multiple quantum well (MQW) structures with up to...
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Article
Electron Transport in the III–V Nitride Alloys
We study electron transport in the alloys of aluminum nitride and gallium nitride and alloys of indium nitride and gallium nitride. In particular, employing Monte Carlo simulations we determine the velocity-fi...
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Article
Pyroelectric and Piezoelectric Properties of Gan-Based Materials
We review pyroelectric and piezoelectric properties of GaN-based materials. Pyroelectric effects in GaN have been studied in two different regimes: (i) uniform sample heating regime and (ii) under applied temp...
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Article
Stimulated Emission at 258 nm in AlN/AlGaN Quantum Wells Grown on Bulk AlN Substrates
We report on observation of stimulated emission at 258 nm in AlN/AlGaN multiple quantum wells. The structures were grown over Al-face single crystal bulk AlN substrates. AlN/AlGaN structures with 50% of Al in ...
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Article
Quaternary AlInGaN MQWs for Ultraviolet LEDs
We report a pulsed atomic layer epitaxy (PALE) growth technique for quaternary AlInGaN films for ultraviolet optoelectronic applications. Using the PALE approach high quality quaternary AlInGaN/AlInGaN multipl...
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Article
High Magnetic Field Studies of AlGaN/GaN Heterostructures Grown on Bulk GaN, SiC, and Sapphire Substrates
We present the results of the high magnetic field studies of properties of two-dimensional electron gas (2DEG) in AlGaN/GaN heterostructures grown over high-pressure bulk GaN, sapphire, and insulating SiC subs...
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Article
Two-dimensional electron gas scattering mechanisms in AlGaN/GaN heterostructures
We present the results of the experimental and theoretical studies of the low field mobility of two-dimensional electrons in the homoepitaxial AlGaN/GaN heterostructures and in the AlGaN/GaN heterostructures g...
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Article
Negative Differential Conductivity in AlGaN/GaN HEMTs: Real Space Charge Transfer from 2D to 3D GaN States?
We report on non-thermal negative differential conductivity (NDC) in AlGaN/GaN HEMTs grown on sapphire substrates by low-pressure MOCVD. The sheet electron density was on the order of few times 1012cm−2 and the H...
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Article
1/f Noise Behavior in Pentacene Organic Thin Film Transistors
We studied the low frequency noise in top-contact pentacene Thin Film Transistors (TFTs). The relative spectral noise density of the drain current fluctuations SI/I2 had a form of 1/f noise in the measured freque...
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Article
Pyroelectric and Piezoelectric Properties of GaN-Based Materials
We review pyroelectric and piezoelectric properties of GaN-based materials. Pyroelectric effects in GaN have been studied in two different regimes: (i) uniform sample heating regime and (ii) under applied temp...
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Article
Polar Optical Phonon Instability and Intervalley Transfer in Gallium Nitride
We develop a simple, one-dimensional, analytical model, which describes electron transport in gallium nitride. We focus on the polar optical phonon scattering mechanism, as this is the dominant energy loss mec...
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Article
A Semi-Analytical Interpretation of Transient Electron Transport in Gallium Nitride, Indium Nitride, and Aluminum Nitride
The energy dependent momentum and energy relaxation times, and the effective single valley energy dependent effective mass, are extracted from Monte Carlo simulations of gallium nitride, indium nitride, and al...
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Article
Double Channel AlGaN/GaN Heterostructure Field Effect Transistor
We report on a Double Channel A1GaN/GaN Heterostructure Field Effect Transistor, where the bottom channel is formed by a GaN-AlGaN-GaN Semiconductor-Insulator-Semiconductor structure. The series resistance for...
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Article
Temperature Dependence of Breakdown Field in p-π-n GaN Diodes
We present the results of the study of the electric breakdown in p-π-n GaN diodes. The breakdown is observed at reverse biases above 40 V and is accompanied by the formation of microplasmas. The study shows that ...
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Article
Velocity Overshoot and Ballistic Electron Transport in Wurtzite Indium Nitride
Using an ensemble Monte Carlo approach, ballistic transport and velocity overshoot effects are examined in InN and compared with those in GaN and GaAs. It is found that the peak overshoot velocity is in genera...
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Article
GaN and Related Materials for High Power Applications
Unique properties of GaN and related semiconductors make them superior for high-power applications. The maximum density of the two-dimensional electron gas at the GaN/AlGaN heterointerface or in GaN/AlGaN quan...
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Article
Characterization and Modeling of Frequency Dispersion in Amorphous Silicon Thin Film Transistors
The large number of localized energy states in amorphous and polysilicon thin film transistors causes non-crystalline effects in both the DC and AC transistor characteristics. The observed frequency dispersion...
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Article
The Velocity-Field Characteristic Of Indium Nitride
We determine the velocity-field characteristic of wurtzite indium nitride using an ensemble Monte Carlo approach. It is found that indium nitride exhibits an extremely high room temperature peak drift velocity...
