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

A. Grier, A. Valavanis, C. Edmunds, J. Shao, J. D. Cooper, G. Gardner, M. J. Manfra, O. Malis, D. Indjin, Z. Ikonić, P. Harrison

Research output: Contribution to journalArticlepeer-review

22 Citations (Scopus)


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.

Original languageEnglish
Article number224308
Number of pages9
JournalJournal of Applied Physics
Issue number22
Early online date11 Dec 2015
Publication statusPublished - 14 Dec 2015
Externally publishedYes


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