Current Applied Physics, Vol.10, No.6, 1407-1410, 2010
Milliwatt-class non-polar a-plane InGaN/GaN light-emitting diodes grown directly on r-plane sapphire substrates
Non-polar a-plane (11 (2) over bar0) light-emitting diodes (LEDs) in InGaN/GaN multiple quantum well structures were successfully fabricated by metal organic chemical vapor deposition (MOCVD) directly grown on r-plane (1 (1) over bar 20) sapphire substrates. The full width at half maximums (FWHMs) of the X-ray rocking curve (XRC) of an a-plane GaN template along the c-and m-axes were measured to be similar to 349 and similar to 533 arcsec, respectively. The optical output power and external quantum efficiency (EQE) at drive currents of 20 mA and 100 mA under direct current operation in on-wafer measurements were 1.24 mW, 2.4% and 100 mA, 1.7%, respectively. The a-plane LED showed 2.8 nm blue shift with change in drive current from 5 mA to 100 mA. The polarization ratio at room temperature was 0.4 and it indicates that the a-plane LED has polarization anisotropy. (C) 2010 Elsevier B.V. All rights reserved.