A alpha-Si: H Thin-Film Phototransistor for a Near-Infrared Touch Sensor

作者：Lee Yeonsung^*; Omkaram Inturu; Park Jozeph; Kim Hyun Suk; Kyung Ki Uk; Park Wook; Kim Sunkook

来源：IEEE Electron Device Letters, 2015, 36(1): 41-43.

DOI：10.1109/LED.2014.2367118

• alpha-Si:H
• IR sensor
• phototransistor
• touch sensor

This letter presents a highly sensitive near-infrared (IR) a -Si:H phototransistor for touch sensor applications. The narrow bandgap of a-Si exhibits a wideband spectrum response from IR to ultraviolet region, where the IR bandpass filter layers allow the a -Si:H phototransistor to respond to the selective IR light uninterrupted by visible light. The time-resolved photoresponse and transfer I V characteristics for the near-IR a -Si:H phototransistor as a function of power at 785-nm illumination allow the observation of fast photoresponse (tau similar to 0.1 ps), high external quantum efficiency (7.52), and high photoresponse. A prototype unit pixel structure for touch sensors composed of amorphous Si-based switching/amplification/near-IR phototransistors and a storage capacitor, is proposed and designed. The overall results suggest that the near-IR a -Si:H phototransistor offers unique possibilities for user-friendly, low-cost, and large-area touch sensors, especially aimed at consumer applications and other areas of optoelectronics.

• 出版日期2015-1