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WideGap2001
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Doping Issues in Wide Band-Gap Semiconductors

Exeter, United Kingdom
21-23 March 2001
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Talk abstract

Temperature Dependent Hole Transport in GaN

D. Lancefield

Department of Physics, School of Physics and Chemistry, University of Surrey, Guildford, Surrey, GU2 7XH, UK

H. Eshghi

Department of Physics, Shahroud University, Shahroud, 316-36155, Iran

The transport properties of Mg doped, p-type GaN films grown by MOCVD have been measured using Hall effect and resistivity measurements over a temperature range from 400 - 50K. The mobility is found to increase slowly over the temperature range from 400 to 200K. Below this temperature the mobility is seen to decrease rapidly, while the corresponding Hall carrier density goes through a minimum before increasing to lower temperatures. These results have been analysed, using a two-band model. This incorporates a simple valence band model, calculated using a relaxation time approximation, and additional transport within an acceptor impurity band. A good fit has been obtained self-consistently to both the mobility and carrier density over a temperature range of 400-120K. We find that neutral impurity scattering plays an important role in limiting the hole mobility while the best fits are obtained assuming an acoustic-deformation potential of ~20eV.