An AlGaN/GaN Dual Channel Triangular Microcantilever Based UV Detector

The UV detection capabilities of III-nitride dual channel triangular microcantilevers, consisting of AlGaN/GaN two-dimensional electron gas channels with an intervening GaN layer, were investigated using 265, 315, and 375 nm illumination. High spectral responsivities, up to 2.3 x 104 A/W, were observed along with a very low dark current of a few pA, which resulted in a detectivity of 4.99 x 108 Jones. A high UV-visible rejection ratio of 104 was also measured between the wavelengths of 265 and 450 nm. A simple analysis of the photogenerated carriers indicates that the high responsivity arises out of a trap related high internal gain mechanism, while the low dark current and high photocurrent are caused by the suspended GaN interchannel layer and tapered channel geometry. The unique combination of high responsivity and detectivity, high gain, low dark currents, and high UV-visible rejection ratio can lead to the design of novel high-performance visible blind and solar blind UV photodetectors.