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

GRIER, Andrew, VALAVANIS, Alex, EDMUNDS, Colin, SHAO, J, COOPER, J. D., GARDNER, G, MANFRA, M. J., MALIS, Oana, INDJIN, Dragan, IKONIC, Zoran and HARRISON, Paul (2015). Coherent vertical electron transport and interface roughness effects in AlGaN/GaN intersubband devices. Journal of Applied Physics, 118 (224308), 224308-1-224308-9.

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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.

Item Type: Article
Research Institute, Centre or Group: Materials and Engineering Research Institute > Thin Films Research Centre
Identification Number: 10.1063/1.4936962
Depositing User: Paul Harrison
Date Deposited: 08 Dec 2015 16:10
Last Modified: 19 Oct 2016 23:47

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