Organic-Inorganic Heterointerfaces for Ultrasensitive Detection of Ultraviolet Light

The performance of graphene field-effect transistors is limited by the drastically reduced carrier mobility of graphene on silicon dioxide (SiO2) substrates. Here we demonstrate an ultrasensitive ultraviolet (UV) phototransistor featuring an organic self-assembled monolayer (SAM) sandwiched between an inorganic ZnO quantum dots decorated graphene channel and a conventional SiO2/Si substrate. Remarkably, the room-temperature mobility of the chemical-vapor-deposition grown graphene channel on the SAM is an order-of-magnitude higher than on SiO2, thereby drastically reducing electron transit-time in the channel. The resulting recirculation of electrons (in the graphene channel) within the lifetime of the photogenerated holes (in the ZnO) increases the photorespoiisivity and gain of the transistor to similar to 10(8) A/W and similar to 3x 10(9), respectively with a UV to visible rejection ratio of,similar to 10(3). Our UV photodetectot device manufacturing is also compatible with current semiconductor processing, and suitable for large volume production.