Resonant tunneling and intersubband absorption in AlN-GaN-superlattices
|Esther Baumann 2, Fabrizio R. Giorgetta 2, Daniel Hofstetter 2, H. Wu 1, William J. Schaff 1, L. F. Eastman 1, Lutz Kirste 3|
1. Cornell University, 425 Philips Hall, Ithaca, NY 14853, United States
We report on intersubband absorption and vertical transport phenomena in regular GaN-AlN-based superlattice structures grown by MBE. We found that for barrier thicknesses larger than about 25 A, the optical intersubband absorption peaks at a much smaller energy than the photovoltage. A simple model based on the oscillator strength of the corresponding transition and the Wentzel-Kramers-Brillouin-method can qualitatively explain the experimental facts. For barrier thicknesses on the order of 20 A, a much smaller shift between the measured intersubband absorption and photovoltage peaks is observed. This energy difference is due to the strong barrier height dependence of the tunneling probability, which favors vertical transport at the upper edge of the minband formed by the excited states.
Presentation: oral at E-MRS Fall Meeting 2004, Symposium C, by Fabrizio R. Giorgetta
See On-line Journal of E-MRS Fall Meeting 2004
Submitted: 2004-04-28 11:51 Revised: 2009-06-08 12:55