Abstract
We report on the growth and transport characteristics of high-density (∼1013cm-2) two-dimensional electron gases confined at the AlGaN/GaN interface grown by plasma-assisted molecular-beam epitaxy on sapphire substrates. For structures consisting of a 25 nm Al 0.30Ga0.70N barrier deposited on a 2 μm insulating GaN buffer, room-temperature mobilities averaging 1400cm2/Vs at a sheet charge density of 1.0×1013cm-2 are consistently achieved. Central to our approach is a sequence of two Ga/N ratios during the growth of the insulating GaN buffer layer. The two-step buffer layer allows us to simultaneously optimize the reduction of threading dislocations and surface morphology. Our measured sheet resistivities as low as 350/ compare favorably with those achieved on sapphire or SiC by any growth method. Representative current-voltage characteristics of high-electron-mobility transistors fabricated from this material are presented.
Original language | English (US) |
---|---|
Pages (from-to) | 1456-1458 |
Number of pages | 3 |
Journal | Applied Physics Letters |
Volume | 81 |
Issue number | 8 |
DOIs | |
State | Published - Aug 19 2002 |
Externally published | Yes |
All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)