Polarization-induced three-dimensional electron slabs in III-V Nitride semiconductors
Abstract
We demonstrate bulk-doping by tailoring polarization charges in the III-V Nitride semiconductor system. We are able to create mobile three-dimensional electron slabs (3DES) without the introduction of donor-impurities in Al_xGa_1-xN alloys by by employing only compositional grading. The electron-slabs exhibit higher mobilities than comparable donor-doped samples, making it an attractive tool for achieving high-conductivity layers. At low temperatures, the three-dimensional carriers show no signs of freeze-out, and coupled with the large reduction of impurity scattering, the mobility remains high ( 3000 cm^2/V ot s). This enables us to perform low-temperature magnetotransport measurements on the 3DES, making it possible to demonstrate strong Shubnikov de-Haas oscillations in a three-dimensional carrier system in the III-V Nitride semiconductors for the first time. From the oscillations, the effective mass is determined to be m^*=0.19m_0, the dominant scattering mechanism is identified as alloy scattering, and the alloy-scattering potential is determined to be V_0=1.8eV. This technique of polarization-doping is used to create three-dimensional carrier densities in the range of 10^17 - 10^18/cm^3, and can be extended. Doping is controlled by two factors - the thickness of graded layers, and the alloy composition. The wide electron slabs offer another playground for study of electron transport in three-dimensions in the presence of high magnetic fields.
- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- March 2003
- Bibcode:
- 2003APS..MAR.R1194J