A New AlGaInP Multiple-Quantum-Well Light-Emitting Diode With a Thin Carbon-Doped GaP Contact Layer Structure

A new AlGaInP multiple quantum-well light-emitting diode (LED) with a thin carbon-doped GaP contact layer and a transparent conducting indium tin oxide film is fabricated and studied. For comparison, the LEDs with different contact layer structures are also included in this work. Experimental results indicate that the LED with a carbon-doped GaP contact layer exhibits a higher output power of 31.4 mW and a higher external quantum efficiency of 9%. The light-output power, under dc 20-mA operation, of this LED is increased by a factor of 18% as compared with that of conventional LEDs. These results are mainly attributed to the significantly lower series resistance and lower optical absorption effect. Moreover, the new device shows the reduced wavelength shift with 1.7-nm variation between 10 and 200 mA in electroluminescence spectrum.