Visible emission from Er-doped GaN grown by solid source molecular beam epitaxy

Visible light emission has been obtained from Er-doped GaN thin films. The GaN was grown by molecular beam epitaxy on sapphire substrates using solid sources (for Ga, Al, and Er) and a plasma gas source for N-2 Above GaN band-gap photoexcitation resulted in strong green emission. The emission spectrum consists of two narrow green lines at 537 and 558 nm and a broad peak at light blue wavelengths (480-510 nm). The narrow lines have been identified as Er transitions from the H-2(11/2) and S-4(3/2) levels to the I-4(15/2) ground state. The intensity of the 558 nm emission decreases with increasing temperature, while the intensity of the 537 nm line actually peaks at similar to 300 K. This effect is explained based on the thermalization of electrons between the two closely spaced energy levels. (C) 1998 American Institute of Physics.