Coherent vertical electron transport and interface roughness effects in AlGaN/GaN intersubband devices
Abstract
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.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Dec 11, 2015
- Source ID
- 10.1063/1.4936962
Entities
People
- Alexander Valavanis
- Andrew T. Grier
- C. Edmunds
- D. Indjin
- G. Gardner
- J. D. Cooper
- J. Shao
- M. J. Manfra
- Oana Malis
- Paul Harrison
- Z. Ikonic
Organizations
- Birck Nanotechnology Center, Purdue University
- Defense Advanced Research Projects Agency
- National Science Foundation
- Purdue University
- Sheffield Hallam University
- University of Leeds