AlN substrates are produced by Physical Vapor Transport (PVT) growth of AlN bulk single crystals followed by post growth processing of the crystals (calibration, slicing, lapping, and polishing). The AlN substrates are suitable for epitaxial growth. The substrates may be used for development of devices such as ultra violet (UV) light emitting diodes (LEDs) and laser diodes (LDs), Piezo-Electric Transducers, SAW devices, RF Transistors, etc.