Trap density of states (DOS) for two amorphous-InGaZnO thin-film transistors are measured by photoexcited charge-collection spectroscopy (PECCS); free charges trapped at a certain energy level are liberated by the corresponding energetic photons and then electrically collected at the source/drain electrodes. During this photoelectric process, the threshold voltage of TFT shifts and its magnitude provides the DOS information of charge traps. According to the PECCS analysis, the TFT with a channel deposited under high sputtering power appeared more stable than the other device prepared with low sputtering power, showing even less than ∼10-10cm -2 as its totally integrated trap density.
Bibliographical noteFunding Information:
Manuscript received December 7, 2010; accepted December 18, 2010. Date of publication February 4, 2011; date of current version February 23, 2011. This work was supported in part by KOSEF (NRL program, Grant 2010-8-0092), BK21 Project. The review of this letter was arranged by Editor W. T. Ng.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Electrical and Electronic Engineering