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Title: Electron transport in unipolar InGaN/GaN multiple quantum well structures grown by NH{sub 3} molecular beam epitaxy

Unipolar-light emitting diode like structures were grown by NH{sub 3} molecular beam epitaxy on c plane (0001) GaN on sapphire templates. Studies were performed to experimentally examine the effect of random alloy fluctuations on electron transport through quantum well active regions. These unipolar structures served as a test vehicle to test our 2D model of the effect of compositional fluctuations on polarization-induced barriers. Variables that were systematically studied included varying quantum well number from 0 to 5, well thickness of 1.5 nm, 3 nm, and 4.5 nm, and well compositions of In{sub 0.14}Ga{sub 0.86}N and In{sub 0.19}Ga{sub 0.81}N. Diode-like current voltage behavior was clearly observed due to the polarization-induced conduction band barrier in the quantum well region. Increasing quantum well width and number were shown to have a significant impact on increasing the turn-on voltage of each device. Temperature dependent IV measurements clearly revealed the dominant effect of thermionic behavior for temperatures from room temperature and above. Atom probe tomography was used to directly analyze parameters of the alloy fluctuations in the quantum wells including amplitude and length scale of compositional variation. A drift diffusion Schrödinger Poisson method accounting for two dimensional indium fluctuations (both in the growth direction and within the wells)more » was used to correctly model the turn-on voltages of the devices as compared to traditional 1D simulation models.« less
Authors:
;  [1] ;  [1] ;  [2] ;  [3]
  1. Materials Department, University of California, Santa Barbara, California 93106 (United States)
  2. (United States)
  3. Graduate Institute of Photonics and Optoelectronics and Department of Electrical Engineering, National Taiwan University, Taipei, Taiwan (China)
Publication Date:
OSTI Identifier:
22410196
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 18; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
77 NANOSCIENCE AND NANOTECHNOLOGY; AMMONIA; COMPARATIVE EVALUATIONS; ELECTRIC POTENTIAL; ELECTRONS; FLUCTUATIONS; GALLIUM NITRIDES; INDIUM COMPOUNDS; LIGHT EMITTING DIODES; MOLECULAR BEAM EPITAXY; POISSON EQUATION; POLARIZATION; QUANTUM WELLS; SAPPHIRE; SCHROEDINGER EQUATION; TEMPERATURE DEPENDENCE; TWO-DIMENSIONAL SYSTEMS