GaN alternating current light-emitting device

We report a new design of the light-emitting device which can be operated under alternating current source directly. The new type alternating current driven light-emitting device (AC LED) can increase the radition area in each bias direction to improve the device efficiency by the Wheatstone Bridge (WB) circuit design. WB-AC LEDs with different designs were fabricated and the electrical and optical characteristics were measured. It is found that the efficiency of the WB-AC LED is influenced by the varied area ratio of the rectified microchip to the central one because of the different current density and forward bias of each microchip. Additionally, the relationship between the area ratio of microchips and the wall plug efficiency of the WB-AC LED has also been discussed. (C) 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.