Graphene-Oxide-Semiconductor photodetector

The photodetection properties of a graphene-oxide-semiconductor (GOS) diode have been extensively investigated by measuring current-voltage characteristics under illumination with light-emitting diode (LED). We demonstrate that the newly developed GOS heterostructure, with graphene as a transparent gate electrode to form the inversion layer at the oxide-semiconductor interface, can function as a GOS field-effect transistor (GOSFET) operable at low temperature (T) down to 1.5 K. By studying the gate tunneling current in the GOSFET, we find that the dark current is below ~ 0.1 nA, which is almost two orders of magnitude smaller than that in graphene-Si (GS) Schottky detector diode. In addition, the GOS diode shows bilateral photoresponse under LED illumination as the polarity of bias voltage on graphene gate is altered. Consequently, it behaves as a p-i-n or n-i-p diode actively controlled by the applied bias. The responsibility R reaches ~ 100 mA/W at T = 100 K, approximately a factor of 100 higher than R of GS diode. Our work paves the way for the implementation of hybrid photodetecting devices fabricated by two-dimensional materials and conventional semiconductors with CMOS integrability.