Abstract: The present invention involves annealing methods for doped gallium nitride (GaN). In one embodiment, one method includes placing, within a heating unit, a silicon carbide (SiC) wafer as a susceptor in close proximity with a doped GaN epilayer, wherein the doped GaN epilayer is either a GaN layer grown on a substrate or a GaN layer that is free standing; and heating, at a heating rate of at least about 100° C./s, the wafer and the doped GaN epilayer to at least about 1200° C. In another embodiment, another method includes placing, within a heating unit, a doped GaN epilayer, wherein the doped GaN epilayer is either a GaN layer grown on a conducting substrate or a GaN layer that is free standing; and heating, at a heating rate of at least about 100° C./s, the doped GaN epilayer to at least about 1200° C.

Abstract: The present invention grows nanostructures using a microwave heating-based sublimation-sandwich SiC polytype growth method comprising: creating a sandwich cell by placing a source wafer parallel to a substrate wafer, leaving a small gap between the source wafer and the substrate wafer; placing a microwave heating head around the sandwich cell to selectively heat the source wafer to a source wafer temperature and the substrate wafer to a substrate wafer temperature; creating a temperature gradient between the source wafer temperature and the substrate wafer temperature; sublimating Si- and C-containing species from the source wafer, producing Si- and C-containing vapor species; converting the Si- and C-containing vapor species into liquid metallic alloy nanodroplets by allowing the metalized substrate wafer to absorb the Si- and C-containing vapor species; and growing nanostructures on the substrate wafer once the alloy droplets reach a saturation point for SiC.