Abstract
We evaluate the Al xGa 1-xN/GaN/Al yGa 1-yN double heterostructure (DH) for heterostructure field-effect transistor applications, where the GaN quantum well is compressively strained on a relaxed crack-free Al yGa 1-yN buffer layer, so that the Al content in the Al xGa 1-xN top barrier can be improved as compared with a conventional Al xGa 1-xN/GaN single heterostructure (SH) with the same strain in the Al xGa 1-xN layer. By self-consistently solving the coupled Schrödinger and Poisson equations, we find that the two-dimensional electron gas (2DEG) sheet density in an Al 0.6Ga 0.4N/GaN/Al 0.3Ga 0.7N DH is 2.59 × 10 13 cm -2, much higher than the 1.71 × 10 13 cm -2 in a conventional A 0.3Ga 0.7N/GaN SH. The 2DEG sheet density increases with increasing Al content x and decreases slightly with increasing y. With a fixed Al content (x-y) ratio, y is the key parameter determining the 2DEG density.
Original language | English (US) |
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Pages (from-to) | 1018-1023 |
Number of pages | 6 |
Journal | Physica Status Solidi (A) Applications and Materials Science |
Volume | 203 |
Issue number | 5 |
DOIs | |
State | Published - Apr 2006 |
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Surfaces and Interfaces
- Surfaces, Coatings and Films
- Electrical and Electronic Engineering
- Materials Chemistry