Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10642343 | Physica E: Low-dimensional Systems and Nanostructures | 2005 | 7 Pages |
Abstract
In this paper we present a study of the effect of GaN capping layer thickness on the two-dimensional (2D)-electron mobility and the two-dimensional electron gas (2DEG) sheet density which is formed near the AlGaN barrier/buffer GaN layer. This study is undertaken using a fully numerical calculation for GaN/AlxGa1âxN/GaN heterostructures with different Al mole fraction in the AlxGa1âxN barrier, and for various values of barrier layer thickness. The results of our analysis clearly indicate that increasing the GaN capping layer thickness leads to a decrease in the 2DEG density. Furthermore, it is found that the room-temperature 2D-electron mobility reaches a maximum value of approximately 1.8Ã103Â cm2Â /Vsâ1 for GaN capping layer thickness grater than 100Â Ã
with an Al0.32Ga0.68N barrier layer of 200Â Ã
thick. In contrast, for same structure, the 2DEG density decreases monotonically with GaN capping layer thickness, and eventually saturates at approximately 6Ã1012Â cmâ2 for capping layer thickness greater than 500Â Ã
. A comparison between our calculated results with published experimental data is shown to be in good agreement for GaN capping layers up to 500Â Ã
thickness.
Keywords
Related Topics
Physical Sciences and Engineering
Materials Science
Electronic, Optical and Magnetic Materials
Authors
A. Asgari, M. Kalafi, L. Faraone,