Fabrication of Heterojunction Diode Based on n-ZnO Nanowires/p-Si Substrate: Temperature Dependent Transport Characteristics

摘要

Herein, we report the growth and characterizations of well-crystalline n-ZnO nanowires assembled in micro flower-shaped morphologies. The nanowires are grown on p-Silicon substrate and characterized in terms of their structural, morphological and electrical properties. Temperature dependent transport characteristics of the fabricated n-ZnO/p-Si heterojunction diode were examined. The morphological studies revealed that the nanowires are grown in high-density and arrange in special micro flower shaped morphology. The structural characterizations confirmed that the nanowires are well-crystalline and possessing wurtzite hexagonal phase. The electrical properties were evaluated by examining the I-V characteristics of the fabricated n-ZnO/p-Si heterojunction diode. The I-V characteristics were studied at temperature < 300 K and >= 300 K in the forward and reverse bias conditions. The detailed temperature dependent electrical properties revealed that the fabricated heterojunction assembly shows a diode-like behavior with a turn-on voltage of 5 V at almost all temperatures and the delivered current changes between similar to 1 to similar to 5 mu A when temperature changes from 77 K to 425 K. The rectifying behavior of the fabricated heterojunction diode, at 5 V, was demonstrated by rectifying ratio of similar to 4 at 77 K which decreases to similar to 1.5 at 425 K. This analysis also showed that the mean potential barrier of the fabricated heterojunction (similar to 1.2 eV) is larger than the energy difference (0.72 eV) of the work functions between Si and ZnO.