Effect of Temperature on the Electrical Characteristics of Nanostructured n-ZnO/p-Si Heterojunction Diode

摘要

This paper describes temperature dependent electrical behavior of n-ZnO/p-Si heterojunction diode. Nanostructured Zinc Oxide (ZnO) thin film was deposited on p-type Silicon (Si) substrate by thermal evaporation technique for fabricating n-ZnO/p-Si heterojunction. XRD results revealed that grown ZnO nanoneedles on p-Si substrate are single crystalline with a hexagonal wurtzite structure. The temperature dependent electrical junction properties were investigated by current-voltage-temperature (I-V-T) measurement. The n-ZnO/p-Si junction exhibits strong rectifying behavior with a rectification ratio (forward current/reverse current) of ~ 102. It is further confirmed that the fabricated p-n heterojunction showed an excellent stability over the temperature range of 15-120 ℃. Temperature-dependent forward current measurement suggests that trap-assisted multi-step tunneling is the dominant carrier transport mechanism in this p-n heterojunction. These results demonstrate the suitability of thermally deposited nanostructure ZnO thin film on Si substrate for fabrication of efficient and low-cost optoelectronic devices for Si-based integrated circuits.