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Interface roughness effects on transport in tunnel structures

Ting, D. Z.-Y. and McGill, T. C. (1996) Interface roughness effects on transport in tunnel structures. Journal of Vacuum Science and Technology B, 14 (4). pp. 2790-2793. ISSN 1071-1023. http://resolver.caltech.edu/CaltechAUTHORS:TINjvstb96

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Abstract

Direct simulations of interface roughness effects on transport properties of tunnel structures are performed using the planar supercell stack method. The method allows for the inclusion of realistic three-dimensional rough interfacial geometries in transport calculations. For double barrier resonant tunneling structures, we used our method to analyze the effect of roughness at each of the four interfaces, and to test for sensitivity of transport properties to island size and height. Our simulations yields the following conclusions: (1) We find that scattering of off-resonance states into on-resonance states provides the dominant contribution to interface roughness assisted tunneling. Analyses of scattering strength sensitivity to interface layer configurations reveals preferential scattering into Delta k parallel to approximate to 2 pi/lambda states, where lambda is the island size. (2) We find that roughness at interfaces adjacent to the quantum well can cause lateral localization of wave functions, which increases with island size and depth. Lateral localization can result in the broadening and shifting of transmission resonances, and the introduction of preferential transmission paths. In structures with wide and tall islands, it is possible to find localization over "islands" as well as localization over "oceans." (3) The leading rough interface is the strongest off-resonance scatterer, while rough interfaces adjacent to quantum well are the strongest on-resonance scatterers. The trailing interface is the weakest scatterer.


Item Type:Article
Additional Information:© 1996 American Vacuum Society. Received: 22 January 1996; accepted: 16 April 1996. This work was supported by the Office of Naval Research (ONR) under Grant No. N00014-92-J-1845. One of the authors (D.Z.T.) acknowledges partial support from Department of Physics, National Tsing Hua University (Hsinchu).
Subject Keywords:TUNNEL DIODES; GALLIUM ARSENIDES; ALUMINIUM ARSENIDES; ROUGHNESS; RESONANCE SCATTERING; COMPUTERIZED SIMULATION; QUANTUM WELLS; HETEROSTRUCTURES; SOLID – SOLID INTERFACES; INTERFACE STRUCTURE; LOCALIZED STATES; TRANSPORT PROCESSES; SIZE EFFECT; TIGHT BINDING APPROXIMATION
Record Number:CaltechAUTHORS:TINjvstb96
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:TINjvstb96
Alternative URL:http://dx.doi.org/10.1116/1.588834
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:4117
Collection:CaltechAUTHORS
Deposited By: Lindsay Cleary
Deposited On:28 Jul 2006
Last Modified:26 Dec 2012 08:57

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