Deep ultraviolet AlGaInN-based light-emitting diodes on Si(111) and sapphire

Ultraviolet light-emitting diodes (LEDs) with emission wavelength as short as 280 nm, grown by gas source molecular beam epitaxy with ammonia, are described. The typical multi-quantum well (MQW) structure LED consists of an AlN buffer layer deposited on Si(111) or sapphire, followed by a (Al)GaN buffer layer and two superlattice structures, n- and p-type, with the MQW active region placed between them. Room temperature Hall measurements of n- and p-type AlN/AlGaInN superlattice structures show average hole concentrations of 1 × 10¹⁸ cm^-3, with mobility of 3-4 cm²/Vs, and electron concentrations of 3 × 10¹⁹ cm^-3, with mobility of 10-20 cm²/Vs. Room temperature electroluminescence spectra of mesa-etched devices show predominant emission at 280 nm.