Plasma assisted molecular beam epitaxial growth of GaN with low growth rates and their properties

A systematic investigation on PA-MBE grown GaN with low growth rates (less than 0.2 mu m/h) has been conducted in a wide growth temperature range, in order to guide future growth of sophisticated fine structures for quantum device applications. Similar to usual growths with higher growth rates, three growth regions have been revealed, namely, Ga droplets, slightly Ga-rich and N-rich 3D growth regions. The slightly Ga-rich region is preferred, in which GaN epilayers demonstrate optimal crystalline quality, which has been demonstrated by streaky RHEED patterns, atomic smooth surface morphology, and very low defect related yellow and blue luminescence bands. The growth temperature is a critical parameter to obtain high quality materials and the optimal growth temperature window (similar to 700-760 degrees C) has been identified. The growth rate shows a strong dependence on growth temperatures in the optimal temperature window, and attention must be paid when growing fine structures at a low growth rate. Mg and Si doped GaN were also studied, and both p- and n-type materials were obtained.

Automated summary

A systematic investigation on low growth rate PA-MBE grown GaN was conducted in a wide growth temperature range, identifying the optimal growth temperature window of 700-760 degrees C. The slightly Ga-rich region was preferred for high-quality GaN epitaxial growth. Mg and Si doped GaN resulted in both p- and n-type materials.