Abstract: AlN single crystals prepared by a novel spontaneous physical vapor transport (PVT) growth approach at 2100-2250 ℃ were etched in molten KOH/NaOH eutectic alloy.All samples were investigated by scanning electron microscope (SEM) after wet-etching, optimal parameters and morphologies for c-plane, r-planes and m-plane of AlN single crystals are obtained.The growth habits and etch pit densities (EPD) of crystals grown by proposed novel spontaneous approach are also revealed.

Key words: AlN single crystals prepared by a novel spontaneous physical vapor transport (PVT) growth approach at 2100-2250 ℃ were etched in molten KOH/NaOH eutectic alloy.All samples were investigated by scanning electron microscope (SEM) after wet-etching, optimal parameters and morphologies for c-plane, r-planes and m-plane of AlN single crystals are obtained.The growth habits and etch pit densities (EPD) of crystals grown by proposed novel spontaneous approach are also revealed.