Electrical characteristics of Mg-doped p-GaN treated with the electrochemical potentiostatic activation method

The electrical characteristics and carrier transport mechanism of Mg-doped p-GaN treated with the electrochemical potentiostatic activation (EPA) method was investigated. The EPA method resulted in lower H concentration up to 56% with a subsequent increase in hole concentration and improved ohmic contacts. The temperature-dependent electrical resistivity of the reference p-GaN followed a similar to T (1/4) dependence, i.e., hopping conduction, while that of the EPA-treated sample began to follow a similar to T (1) behavior involving band conduction. This was due to the reduced density of deep-level states associated with the Mg-H complex, e. g., from 1.28 x 10(19) to similar to 7.50 x 10(18) cm (3) after EPA treatment. The increase in the hole concentration was responsible for the enhanced ohmic contact via tunneling. (C) 2013 Elsevier B. V. All rights reserved.