Non-polar
a-plane (11-20)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 (11-20) 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 ∼349
and ∼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.
Source:Current
Applied Physics
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