Mg doping of GaN grown by plasma-assisted molecular beam epitaxy under nitrogen-rich conditions

Acceptor doping of GaN with Mg during plasma-assisted molecular beam epitaxy, under N-rich conditions and a relatively high growth temperature of 740 degrees C, was investigated. The p-doping level steadily increases with increasing Mg flux. The highest doping level achieved, determined from Hall measurements, is 2.1x10(18) cm(-3). The corresponding doping efficiency and hole mobility are similar to 4.9% and 3.7 cm(2)/V s at room temperature. Cross-sectional transmission electron microscopy and photoluminescence measurements confirm good crystalline and optical quality of the Mg-doped layers. An InGaN/GaN quantum dot light emitting diode (lambda(peak)=529 nm) with p-GaN contact layers grown under N-rich condition exhibits a low series resistance of 9.8 .