Green emission from Er-doped GaN grown by molecular beam epitaxy on Si substrates

Visible light emission has been obtained from Er-doped α-GaN thin films grown on Si(111). The GaN was grown by molecular beam epitaxy using solid sources (for Ga and Er) and a plasma gas source for N2. Photoexcitation with a He–Cd laser resulted in strong green emission from two narrow green lines at 537 and 558 nm identified as Er transitions from the H11/22 and S3/24 levels to the I15/24 ground state. X-ray diffraction shows the GaN:Er to be a wurtzitic single crystal film. The growth temperature is seen to have a strong effect on the GaN:Er surface morphology.