| Autor: |
Heikman, Sten, Keller, Stacia, Wu, Yuan, Speck, James S., DenBaars, Steven P., Mishra, Umesh K. |
| Předmět: |
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| Zdroj: |
Journal of Applied Physics; 6/15/2003, Vol. 93 Issue 12, p10114, 5p, 1 Black and White Photograph, 1 Diagram, 4 Graphs |
| Abstrakt: |
The influence of AlGaN and GaN cap layer thickness on Hall sheet carrier density and mobility was investigated for Al[SUB0.32]Ga[SUB0.68]N/GaN and GaN/Al[SUB0.32]Ga[SUB0.68]N/GaN heterostructures deposited on sapphire substrates. The sheet carrier density was found to increase and saturate with the AlGaN layer thickness, while for the GaN-capped structures it decreased and saturated with the GaN cap layer thickness. A relatively close fit was achieved between the measured data and two-dimensional electron gas densities predicted from simulations of the band diagrams. The simulations also indicated the presence of a two-dimensional hole gas at the upper interface of GaN/AlGaN/GaN structures with sufficiently thick GaN cap layers. A surface Fermi-level pinning position of 1.7 eV for AlGaN and 0.9-1.0 eV for GaN, and an interface polarization charge density of 1.6 × 10[SUP13] - 1.7 × 10[SUP13] cm[SUP-2], were extracted from the simulations. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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