Quasi-equilibrium crystal shapes and kinetic Wulff plots for gallium nitride grown by hydride vapor phase epitaxy

In this paper we demonstrate work on developing the kinetic Wulff plots and quasi-equilibrium crystal shapes of GaN by hydride vapor phase epitaxy to understand the stable polar, semipolar, and nonpolar planes that emerge naturally from the GaN crystal. High quality bulk m-plane GaN substrates were masked with circular openings to perform selective area growth studies. Growths were performed by hydride vapor phase epitaxy over a range of temperatures, pressures and carrier gases. The quasi-equilibrium crystal shapes were shown to have clear m  -plane {11¯00} facets and a sharp and flat (0001¯) N-face or c− face. The (0001) Ga-face or c+ face became faceted with {101¯1} planes emerging with reduced pressures and temperatures. Based on the stable facets, kinetic Wulff plots were constructed.

► Demonstrated SAG of GaN on high quality bulk GaN substrates by HVPE. ► Islands from these growths reveal the QECS of GaN under varying growth ranges. ► QECS of GaN is shown to have clear m  -plane facets and flat N-face. ► Ga-face became faceted with {101¯1} planes with reduced pressures and temperatures. ► From this information the kinetic Wulff plots of GaN were constructed.