Engineering of band gap states of amorphous SiZnSnO semiconductor as a function of Si doping concentration.
We investigated the band gap of SiZnSnO (SZTO) with different Si contents. Band gap engineering of SZTO is explained by the evolution of the electronic structure, such as changes in the band edge states and band gap. Using ultraviolet photoelectron spectroscopy (UPS), it was verified that Si atoms can modify the band gap of SZTO thin films. Carrier generation originating from oxygen vacancies can modify the band-gap states of oxide films with the addition of Si. Since it is not easy to directly derive changes in the band gap states of amorphous oxide semiconductors, no reports of the relationship between the Fermi energy level of oxide semiconductor and the device stability of oxide thin film transistors (TFTs) have been presented. The addition of Si can reduce the total density of trap states and change the band-gap properties. When 0.5 wt% Si was used to fabricate SZTO TFTs, they showed superior stability under negative bias temperature stress. We derived the band gap and Fermi energy level directly using data from UPS, Kelvin probe, and high-resolution electron energy loss spectroscopy analyses.
Korea University, Department of Electrical Engineering, Seoul, 136-701, Republic of Korea.
Jun Young
JY
Choi
Korea University, Department of Electrical Engineering, Seoul, 136-701, Republic of Korea.
Keun
K
Heo
Samsung Advanced Institute of Technology, Device Lab, Suwon-si, 443-803, Republic of Korea.
Kyung-Sang
KS
Cho
Samsung Advanced Institute of Technology, Device Lab, Suwon-si, 443-803, Republic of Korea.
Sung Woo
SW
Hwang
Korea University, Department of Electrical Engineering, Seoul, 136-701, Republic of Korea.
Sangsig
S
Kim
Cheongju University, Department of Semiconductor Engineering, Cheongju, 360-764, Republic of Korea.
Sang Yeol
SY
Lee