Single-crystal zincblende GaN growth on GaP[100] substrate in molecular beam epitaxy

Zincblende GaN (/spl beta/-GaN) has recently attracted much attention because of its significant advantages over wurtzite GaN (/spl alpha/-GaN), such as higher doping efficiencies, higher carrier mobilities, and the possibility of optoelectronic integration with GaAs or Si devices. Due to its metastability, however, it is difficult to obtain single-crystalline /spl beta/-GaN. Several groups reported that As or P overpressure was beneficial to enhance the growth of /spl beta/-GaN without phase mixture. We report the growth of single-crystalline /spl beta/-GaN epilayers achieved by varying the V/III ratio of a GaN nucleation layer (NL) grown on a GaP[100] substrate. Adjustment of the V/III ratio in an NL stage resulted in phase transition from wurzite to zincblende GaN. GaP[100] was employed as a substrate because of its smaller difference in lattice constants and thermal expansion coefficients with those of GaN, compared to GaAs, and, especially because of the possibility of growing,/spl beta/-GaN on GaP[100]/Si[100].