Electronic states in modulation doped p-AlGaN/GaN superlattices
- 15 October 2001
- journal article
- research article
- Published by AIP Publishing in Journal of Applied Physics
- Vol. 90 (8) , 4032-4038
- https://doi.org/10.1063/1.1405819
Abstract
The properties of p- AlGaN/GaN modulation dopedsuperlattices(SLs) prepared by molecular beam epitaxy were studied by means of conductivity versus temperature, admittance spectroscopy, photoinduced current spectroscopy, microcathodoluminescence (MCL) spectra measurements, and measurements of effective diffusion lengths. It is shown that in SLs grown on GaN underlayers the sheet resistivity is about two orders of magnitude lower than for reference p- GaN films and the resistivity of SLs remains lower up to temperatures of about 350 °C. For SLs grown on AlGaN underlayers the gain in resistivity is much more moderate and certain advantages in using such SLs are envisaged only for temperatures below room temperature. The reason for this lower gain is a considerable decrease in hole mobility compared to p- GaN . The effect is somewhat tentatively attributed to worse crystalline perfection of these SLs. It is also shown that such SLs are characterized by a strongly broadened MCL peak and the presence of additional hole traps with activation energy of about 0.4 eV. Despite that, the photosensitivity and MCL intensity of these SLs are much better than for reference p- GaN samples.This publication has 23 references indexed in Scilit:
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