Wavelength Shift in Nonpolar a-Plane LEDs

The as-grown samples were investigated by optical microscopy and room temperature PL measurements. 300 x 300 gm square diode were defined by chlorine-based RIE. Electron beam deposited Pd/Au (20/200 nm) and Al/Au (30/300 nm) were used as p-GaN and n-GaN contacts, respectively. For packaging, the wafer was diced into discrete dies for attachment to submounts. Conventional die-bonding and wire-bonding techniques were then apphed, and the individual LEDs were packaged into conventional epoxy-encapsulated lamps. The electrical and luminescence characteristics of the diode were 

Schematic cross-section of the m-plane InGaN/GaN light-emitting diode 

The pulse width and duty cycle were set at 20 0,s and 10%, respectively, and the drive current was varied from 3 to 500 mA. The devices emitted in the blue spectral range with an emission peak of 452 nm for drive currents in excess of 50 mA. An initial blue shift from 460 to 452 nm, observed when the drive current was increased from 3 to 50 mA (not shown in the figure), was attributed to the band filling of localized states [34]. Wavelength shift was not observed for drive currents above 50 mA and up to 1 A, even for low duty cycles. 

4 Transmission Through Free-standing m-plane Substrate 

12 Nonpolar Nitride Heterostructures and Devices grown by MOCVD 1E+22- 

---