The effects of deposition temperature and ambient on the physical and electrical performance of DC-sputtered n-ZnO/p-Si heterojunction

Abstract

The effects of deposition conditions on the physical and electrical performance of the n-ZnO/p-Si heterojunction were systematically investigated. ZnO films were deposited on the Si and glass substrates using direct current (DC) magnetron sputtering with various ambients and substrate temperatures. The results showed that increasing the O₂ content and substrate temperature during the deposition process could improve the crystallinity and stoichiometry of the ZnO film, resulting in a lower carrier concentration and higher resistivity. The electrical properties of the n-ZnO/p-Si heterojunctions were also affected by the deposition parameters. For the junctions fabricated in the pure Ar ambient, the sample deposited at room temperature (RT) showed Ohmic behavior, while the one deposited at 300 °C exhibited poor rectifying behavior. On the other hand, the junctions fabricated in the O₂/Ar ambient possessed ideal rectifying behaviors. The different carrier transport mechanisms for the heterojunctions under forward and reverse bias were systematically studied using a high temperature current–voltage (I-V) measurement. The recombination-tunneling current showed temperature insensitive performance while the space-charge limited current (SCLC) changed with the measurement temperature.