High performance AlGaInP LEDs using reactive thermally evaporated transparent conducting indium-tin-oxide (ITO)

Reactive thermally evaporated transparent conducting Indium-Tin-Oxide (ITO) layers are used as window material and current spreading layer on AlGaInP Light Emitting Diodes (LEDs). The sheet resistance of the ITO films deposited is of the order 4.5 ohm/sq with up to 90% transmission in the visible region of the spectrum. Optimum thickness of the p and n-type AlGaInP cladding and the top p/sup +/GaAs epitaxial layers were determined. The LEDs fabricated emit light with a peak wavelength (/spl lambda/p) at 600 nm and Full Width at Half Maximum (FWHM) of 15 nm. A forward voltage of 1.71 V at 20 mA was obtained. In all cases the devices incorporating the ITO layer gave a marginally greater output (10%) than the standard non-ITO devices.