Green electroluminescence from Er-doped GaN Schottky barrier diodes

Visible light electroluminescence (EL) has been obtained from Er-doped GaN Schottky barrier diodes. The GaN was grown by molecular beam epitaxy on Si substrates using solid sources (for Ga, and Er) and a plasma source for N-2. Al was utilized for both the Schottky (small-area) and ground (large-area) electrodes. Strong green light emission was observed under reverse bias, with weaker emission present under forward bias. The emission spectrum consists of two narrow green lines at 537 and 558 nm and minor peaks at 413 and at 666/672 nm. The green emission lines have been identified as Er transitions from the H-2(11/12) and S-4(3/2) levels to the I-4(15/2) ground state and the blue and red peaks as the H-2(9/2) and F-4(9/2) Er transitions to the same ground state. The reverse bias EL intensity was found to increase linearly with bias current. (C) 1998 American Institute of Physics. [S0003-6951(98)00343-X].