SnO2/ZnO/p-Si and SnO2/TiO2/p-Si heterojunction UV photodiodes prepared using a hydrothermal method

Low dimensional nanostructures (NSs) exhibit superior properties for the fabrication of electronic and optoelectronic devices. The integration of these structures into the semiconductor devices is a novel efficient way to achieve high performance heterojunction UV photodiodes due to the enhanced light harvesting and facilitated charge-transfer. Herein, we report the effect of the type of metal oxide seed layers on the formation of SnO2 NSs and the performance of SnO2/p-Si heterojunction UV photodiodes. The seed layers were fabricated by depositing ZnO and TiO2 thin films (TFs) on p-Si substrate by spin-coating method. The synthesis of SnO2 NSs on each seed layers was achieved by hydrothermal growth technique. It was found that the morphology of nanostructures and light sensing performance of the heterojunction UV photodiodes were significantly influenced by type of seed layers. The photoresponsivity of our fabricated devices were found to be 68 mA/W for SnO2-NSs/ZnOTF/p-Si (device-1) and 92 mA/W for SnO2-NSs/TiO2-TF/p-Si (device-2). Thus, the device-2 is considered to be a better choice over the device-1 for UV detection applications. This research might shed light on new approaches to boost the performance of the heterojunction UV photodiodes. (C) 2020 Elsevier B.V. All rights reserved.