Acceptor formation in Mg-doped, indium-rich Ga x In1−x N: evidence for p-type conductivity
1 Department of Computer Science and Electronic Engineering, University of Essex, Colchester, CO4 3SQ, UK
2 Department of Physics, Anadolu University, Eskişehir, 26470, Turkey
3 Faculty of Science, Department of Physics, Istanbul University, Vezneciler, Istanbul, 34134, Turkey
4 Université de Toulouse, LPCNO, INSA-UPS-CNRS, 135 Avenue de Rangueil, Toulouse, 31077, France
5 Department of Physics, Cukurova University, Adana, 01330, Turkey
Nanoscale Research Letters 2012, 7:574 doi:10.1186/1556-276X-7-574Published: 18 October 2012
We report on the Mg-doped, indium-rich GaxIn1−xN (x < 30). In the undoped material, the intrinsic electron density is very high and as a result there is no detectable photoconductivity (PC) signal within the range of temperatures of 30 < T < 300 K. In the Mg-doped material however, where the conductivity is reduced, there is a strong PC spectrum with two prominent low-energy peaks at 0.65 and 1.0 eV and one broad high-energy peak at around 1.35 eV. The temperature dependence of the spectral photoconductivity under constant illumination intensity, at T > 150 K, is determined by the longitudinal-optical phonon scattering together with the thermal regeneration of non-equilibrium minority carriers from traps with an average depth of 103 ± 15 meV. This value is close to the Mg binding energy in GaInN. The complementary measurements of transient photoluminescence at liquid He temperatures give the e-A0 binding energy of approximately 100 meV. Furthermore, Hall measurements in the Mg-doped material also indicate an activated behaviour with an acceptor binding energy of 108 ± 20 meV.