The photocurrent (IPH) of amorphous InZnO thin film transistors in the off-state is investigated as a function of incident optical power (P). The results show that IPH exhibits a nonlinear dependence on P. Additionally, the dependence of IPH on P exhibits a strong photon energy (hυ)-dependent feature. When P is relatively low, IPH is shown to be proportional to Pγ, where γ is greater than 1. The γ > 1 behavior may be ascribed to the source-barrier-lowering effect due to the accumulation of photo-induced positive charges at the source side. When P is relatively high, while IPH remains proportional to Pγ under the incident light with hυ larger than the optical bandgap (Eg) of a-IZO, it turns to increase at an exponential rate with P if hυ of the incident light is smaller than the Eg. The exponential increase in IPH is attributed to the source-barrier-thinning effect, which leads to a significantly enhanced tunneling current.
Nonlinear photocurrent-intensity behavior of amorphous InZnO thin film transistors
Huiling Lu, Xiaoliang Zhou, Ting Liang, Letao Zhang, Shengdong Zhang; Nonlinear photocurrent-intensity behavior of amorphous InZnO thin film transistors. Appl. Phys. Lett. 22 January 2018; 112 (4): 042103. https://doi.org/10.1063/1.5011687
Download citation file: