Physical modeling for photo-capacitance characteristics of metal oxide TFTs
Haoyang Li,
Wencai Zuo,
Feifan Li,
Zhaohua Zhou,
Miao Xu,
Lei Wang,
Weijing Wu,
Junbiao Peng
Affiliations
Haoyang Li
State Key Laboratory of Luminescent Materials and Devices, Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Guangzhou 510640, China
Wencai Zuo
State Key Laboratory of Luminescent Materials and Devices, Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Guangzhou 510640, China
Feifan Li
State Key Laboratory of Luminescent Materials and Devices, Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Guangzhou 510640, China
Zhaohua Zhou
State Key Laboratory of Luminescent Materials and Devices, Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Guangzhou 510640, China
Miao Xu
State Key Laboratory of Luminescent Materials and Devices, Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Guangzhou 510640, China
Lei Wang
State Key Laboratory of Luminescent Materials and Devices, Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Guangzhou 510640, China
Weijing Wu
State Key Laboratory of Luminescent Materials and Devices, Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Guangzhou 510640, China
Junbiao Peng
State Key Laboratory of Luminescent Materials and Devices, Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Guangzhou 510640, China
We propose an amorphous metal oxide thin film transistor photo-capacitance model in the depletion region that takes Fermi level splitting and band-bending rearrangement into consideration. The split Fermi level is used to characterize the variation in trapped electrons under illumination. Those trapped electrons are excited by optical energy transport under the electric field induced by gate voltage, changing the charge density in the space charge and inducing the rearrangement of band bending. By comparing the data calculated from the model with the test data under three different illumination conditions, that is, 808, 635, and 520 nm, we verify the correctness of this model. Furthermore, the fitting results were in accordance with the general law: the higher the photon energy, the higher the energy level splitting.
