High-Efficiency ZnO-Based Ultraviolet Photodetector with Integrated Single-Walled Carbon Nanotube Thin-Film Heater

Recently, sol-gel-derived ZnO thin films have been explored for high performance photodetectors (PDs). However, the crystallinity of sol-gel-derived ZnO films is inferior to vacuum-based grown ZnO film, leading to poor photoreaction in the PDs. This study combines a single-walled carbon nanotube (SWCNT) heating system with sol-gel ZnO-based ultraviolet (UV) PDs. A SWCNT heater is fabricated on sapphire substrates using spin coating technique, resulting in a transparent heater with a transmittance of approximate to 80% by controlling spin speed. In addition, increasing the number of SWCNT spin coatings from 1 to 3 raises the heater temperature to over 170 degrees C, resulting in a response time of less than 1 min. The sol-gel ZnO-based UV PDs with the SWCNT heater shows a 137% increase in photocurrent as the SWCNT heater temperature increases from 25 to 112 degrees C. In addition, the increase in temperature of the embedded-SWCNT heater significantly shortens the rise and decay times of the sol-gel-derived ZnO PDs.