An edge-contacted pn-heterojunction of a p-SWCNT/n-WO3 thin film

We report a heterojunction formed between single-wall carbon nanotubes (SWCNTs) and a WO3 thin film. WO3 thin films were fabricated by sputter deposition of W followed by oxidation and SWCNTs were fabricated by the arc-discharge method. The morphology of the structures was examined by scanning electron microscopy, X-ray diffraction, and Raman spectroscopy. The current-voltage characteristics of WO3 thin films, SWCNTs films, and SWCNT/WO3 heterojunctions were measured in darkness and under ultraviolet light. A rectifying heterojunction formation of p-SWCNT/n-WO3 was confirmed. The observed unconventional optoelectronic properties were analyzed, and the results were used to explain the photoconduction phenomena occurring at the heterojunction. The heterojunctions and resistors were also examined for their photodetection performance.