We report that a pulsed negative bias stress slightly deteriorates the photoelectric stability of amorphous InGaZnO thin-film transistors, whereas a dc negative bias stress induces a large threshold voltage shift under the light. In the case of pulsed bias stresses, many of photoexcited positive charges might be recombined during the interval between pulses while those charges under dc bias drift to the channel interface without recombination. Interfacial trap density measurements explain the effects of such photoexcited positive charges on the interface.
Bibliographical noteFunding Information:
Manuscript received August 10, 2011; revised August 26, 2011; accepted September 3, 2011. Date of publication October 19, 2011; date of current version November 23, 2011. This work was supported in part by the National Research Foundation through the National Research Laboratory Program under Grant 2011-0000375 and through Brain Korea 21 Project. The review of this letter was arranged by Editor A. Flewitt.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Electrical and Electronic Engineering