Wafer-scale arrayed p-n junctions based on few-layer epitaxial GaTe

摘要

Two-dimensional (2D) materials have attracted substantial attention inelectronic and optoelectronic applications with superior advantages of beingflexible, transparent and highly tunable. Gapless graphene exhibitsultra-broadband and fast photoresponse while the 2D semiconducting MoS2 andGaTe unveil high sensitivity and tunable responsivity to visible light.However, the device yield and the repeatability call for a further improvementof the 2D materials to render large-scale uniformity. Here we report alayer-by-layer growth of wafer-scale GaTe with a hole mobility of 28.4 cm2/Vsby molecular beam epitaxy. The arrayed p-n junctions were developed by growingfew-layer GaTe directly on three-inch Si wafers. The resultant diodes revealgood rectifying characteristics, photoresponse with a maximum photoresponsivityof 2.74 A/W and a high photovoltaic external quantum efficiency up to 62%. Thephotocurrent reaches saturation fast enough to capture a time constant of 22{\mu}s and shows no sign of device degradation after 1.37 million cycles ofoperation. Most strikingly, such high performance has been achieved across theentire wafer, making the volume production of devices accessible. Finally,several photo-images were acquired by the GaTe/Si photodiodes with a reasonablecontrast and spatial resolution, demonstrating for the first time the potentialof integrating the 2D materials with the silicon technology for noveloptoelectronic devices.