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Title: Coherent vertical electron transport and interface roughness effects in AlGaN/GaN intersubband devices

We investigate electron transport in epitaxially grown nitride-based resonant tunneling diodes (RTDs) and superlattice sequential tunneling devices. A density-matrix model is developed, and shown to reproduce the experimentally measured features of the current–voltage curves, with its dephasing terms calculated from semi-classical scattering rates. Lifetime broadening effects are shown to have a significant influence in the experimental data. Additionally, it is shown that the interface roughness geometry has a large effect on current magnitude, peak-to-valley ratios and misalignment features; in some cases eliminating negative differential resistance entirely in RTDs. Sequential tunneling device characteristics are dominated by a parasitic current that is most likely to be caused by dislocations; however, excellent agreement between the simulated and experimentally measured tunneling current magnitude and alignment bias is demonstrated. This analysis of the effects of scattering lifetimes, contact doping and growth quality on electron transport highlights critical optimization parameters for the development of III–nitride unipolar electronic and optoelectronic devices.
Authors:
; ; ; ;  [1] ; ; ;  [2] ;  [3] ;  [4] ;  [2] ;  [4] ;  [4] ;  [4] ;  [5]
  1. Institute of Microwaves and Photonics, School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT (United Kingdom)
  2. Department of Physics, Purdue University, West Lafayette, Indiana 47907 (United States)
  3. Birck Nanotechnology Center, West Lafayette, Indiana 47907 (United States)
  4. (United States)
  5. Materials and Engineering Research Institute, Sheffield Hallam University, Sheffield S1 1WB (United Kingdom)
Publication Date:
OSTI Identifier:
22493029
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 118; Journal Issue: 22; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ALUMINIUM NITRIDES; DENSITY MATRIX; DISLOCATIONS; ELECTRIC CURRENTS; ELECTRIC POTENTIAL; ELECTRON TRANSFER; EPITAXY; EXPERIMENTAL DATA; GALLIUM NITRIDES; OPTOELECTRONIC DEVICES; ROUGHNESS; SCATTERING; SIMULATION; SUPERLATTICES; TUNNEL DIODES; TUNNEL EFFECT