Temperature dependent transport and photoresponse properties of a Mn-doped ZnO/p-Si heterojunction

A Mn-doped ZnO (ZMO) thin film was deposited on a p-Si (100) substrate by magnetron sputtering technology. The structure and morphology of the film were tested by x-ray diffraction and atomic force microscopy. The temperature dependent transport and photoresponse properties of the ZMO/Si heterojunction were also investigated. Results show that the ZMO film was successfully deposited in the polycrystalline structure with a smooth and crack-free surface. The current–voltage (I–V) curves show that the heterojunction exhibits excellent rectifying behavior. As temperature is decreased, the ideality factor of the heterojunction becomes remarkably large, implying a significant change of transport mechanism with differing temperatures. Photocurrent can emerge by illumination. Under reverse bias, the photocurrent increases drastically with the increase of reverse bias and then becomes saturated beyond a certain voltage. In addition, the critical voltage increases with the increase of temperature.