A α-Si:H thin-film phototransistor for a near-infrared touch sensor

Yeonsung Lee, Inturu Omkaram, Jozeph Park, Hyun Suk Kim, Ki Uk Kyung, Wook Park, Sunkook Kim

Research output: Contribution to journalArticlepeer-review

16 Scopus citations

Abstract

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 (τ ∼ 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.

Original languageEnglish
Article number6949127
Pages (from-to)41-43
Number of pages3
JournalIEEE Electron Device Letters
Volume36
Issue number1
DOIs
StatePublished - 1 Jan 2015

Keywords

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

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