Carbon-Related Deep-Level Defects and Turn-On Recovery Characteristics in AlGaN/GaN Hetero-Structures

2014 ◽  
Vol 1635 ◽  
pp. 109-114
Author(s):  
Yoshitaka Nakano ◽  
Yoshihiro Irokawa ◽  
Masatomo Sumiya ◽  
Yasunobu Sumida ◽  
Shuichi Yagi ◽  
...  
Keyword(s):  
Buffer Layer ◽  
Deep Level ◽  
Electron Gas ◽  
Two Dimensional ◽  
Dimensional Electron ◽  
Impurity Incorporation ◽  
Two Dimensional Electron Gas ◽  
Turn On ◽  
Dimensional Electron Gas ◽  
Gan Buffer Layer

ABSTRACTWe have investigated on a relation between C-related deep-level defects and turn-on recovery characteristics in bulk regions of AlGaN/GaN hetero-structures containing various C concentrations, employing their Schottky barrier diodes. With decreasing the growth temperature of the GaN buffer layer, three specific deep-level defects located at ∼2.07, ∼2.75, and ∼3.23 eV below the conduction band were significantly enhanced probably due to the C impurity incorporation into the GaN buffer layer. Among them, the ∼2.75 and ∼3.23 eV levels are considered to be strongly responsible for the two-dimensional electron gas (2DEG) carrier trapping in the bulk regions of the hetero-structures, from their turn-on current recovery characteristics under various optical illuminations.

Band Gap States in AlGaN/GaN Hetero-Interface Studied by Deep-Level Optical Spectroscopy

2009 ◽  
Vol 1202 ◽  
Author(s):  
Yoshitaka Nakano ◽  
Keiji Nakamura ◽  
Yoshihiro Irokawa ◽  
Masaki Takeguchi
Keyword(s):  
Steady State ◽  
Optical Spectroscopy ◽  
Deep Level ◽  
Electron Gas ◽  
Two Dimensional ◽  
Dimensional Electron ◽  
Two Dimensional Electron Gas ◽  
Capacitance Voltage ◽  
Dimensional Electron Gas ◽  
Gap States

AbstractPlanar Pt/AlGaN/GaN Schottky barrier diodes (SBDs) have been characterized by capacitance-voltage and capacitance deep-level optical spectroscopy measurements, compared to reference Pt/GaN:Si SBDs. Two specific deep levels are found to be located at ∼1.70 and ∼2.08 eV below the conduction band, which are clearly different from deep-level defects (Ec - 1.40, Ec - 2.64, and Ec - 2.90 eV) observed in the Pt/GaN:Si SBDs. From the diode bias dependence of the steady-state photocapacitance, these levels are believed to stem from a two-dimensional electron gas (2DEG) region at the AlGaN/GaN hetero-interface. In particular, the 1.70 eV level is likely to act as an efficient generation-recombination center of 2DEG carriers.

Hydrostatic and uniaxial stress dependence and photo induced effects on the channel conductance of n-A1GaN/GaN heterostructures grown on sapphire substrates

1999 ◽  
Vol 572 ◽  
Author(s):  
A. K. Fung ◽  
C. Cai ◽  
P. P. Ruden ◽  
M. I. Nathan ◽  
M. Y. Chen ◽  
...  
Keyword(s):  
Deep Level ◽  
Hydrostatic Stress ◽  
Electron Gas ◽  
Uniaxial Stress ◽  
Organic Chemical ◽  
Two Dimensional ◽  
Dimensional Electron ◽  
Channel Conductance ◽  
Two Dimensional Electron Gas ◽  
Dimensional Electron Gas

ABSTRACTWe measure the hydrostatic stress, uniaxial stress, and photo induced dependence of the channel conductance of two-dimensional electron gas AlGaN/GaN heterostructures grown on c-axis sapphire. The structures examined are grown by nitrogen-plasma molecular beam epitaxy and metal organic chemical vapor deposition. Electrical conductance measurements are made with four point probes on Hall bar samples. Both, hydrostatic stress and uniaxial stress result in changes in the conductance. Moreover, these changes in conductance have long settling times after the stress is applied and may be due to deep level defects, the energy levels of which change with stress. Stress coefficients extracted from the samples are partially attributed to deep level defects and to the piezoelectric effect resulting from different piezoelectric coefficients of GaN and AlN. Photo induced changes of the two-dimensional electron gas are also observed. We find that pulsed illumination produces long transient times in the conductance. These transients are reduced by thermal heating in some samples. However, they can still be present at 153°C.

Anisotropic bilinear magnetoresistance in (110) SrTiO3 -based two-dimensional electron gas

2021 ◽  
Vol 104 (4) ◽  
Author(s):  
Jine Zhang ◽  
Hui Zhang ◽  
Xiaobing Chen ◽  
Jing Zhang ◽  
Shaojin Qi ◽  
...  
Keyword(s):  
Electron Gas ◽  
Two Dimensional ◽  
Dimensional Electron ◽  
Two Dimensional Electron Gas ◽  
Dimensional Electron Gas

scholarly journals Deformation of the Fermi surface of a spinless two-dimensional electron gas in presence of an anisotropic Coulomb interaction potential

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Orion Ciftja
Keyword(s):  
Fermi Surface ◽  
Coulomb Interaction ◽  
Interaction Potential ◽  
Fermi Liquid ◽  
Energy State ◽  
Electron Gas ◽  
Two Dimensional ◽  
Dimensional Electron ◽  
Two Dimensional Electron Gas ◽  
Dimensional Electron Gas

AbstractWe consider the stability of the circular Fermi surface of a two-dimensional electron gas system against an elliptical deformation induced by an anisotropic Coulomb interaction potential. We use the jellium approximation for the neutralizing background and treat the electrons as fully spin-polarized (spinless) particles with a constant isotropic (effective) mass. The anisotropic Coulomb interaction potential considered in this work is inspired from studies of two-dimensional electron gas systems in the quantum Hall regime. We use a Hartree–Fock procedure to obtain analytical results for two special Fermi liquid quantum electronic phases. The first one corresponds to a system with circular Fermi surface while the second one corresponds to a liquid anisotropic phase with a specific elliptical deformation of the Fermi surface that gives rise to the lowest possible potential energy of the system. The results obtained suggest that, for the most general situations, neither of these two Fermi liquid phases represent the lowest energy state of the system within the framework of the family of states considered in this work. The lowest energy phase is one with an optimal elliptical deformation whose specific value is determined by a complex interplay of many factors including the density of the system.

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