Dependence of Photosensitive Effect on the Defects Created by DC Stress for LTPS TFTs

In this letter, the photosensitive effect of n-type low-temperature polycrystalline silicon (LTPS) thin-film transistors (TFTs) after DC stress was investigated. It was discovered that the photo-generated carrier behaviors under optical illumination are related to defect types created by different stress conditions of hot-carrier effect and self-heating effect. These two types of defect creation result in the different photosensitivity behaviors of LTPS TFT. A model considering the relation between photosensitivity and defect is proposed to explain the anomalous illumination behaviors after device degradation.