Stimulated emission at 300 K from photopumped GaN grown by plasma-assisted molecular beam epitaxy with an inductively coupled plasma source

GaN epilayers have been grown on basal plane (0001) sapphire by plasma-assisted molecular beam epitaxy (MBE) with a novel, inductively coupled nitrogen plasma source. Films grown at 700 °C generate stimulated emission at 300 K when optically pumped in vertical geometry with ∼3.5 eV (λ = 355 nm) photons. The extrapolated pump power threshold is ∼3.6 MW cm^-2 which corresponds to an absorbed value of 700 kW cm^-2 and a peak carrier number density of ∼4×1019 cm-3.