title: Dual electrical behavior of multivalent metal cation-based oxide and its application to thin-film transistors with high mobility and excellent photobias stability.
abstract: The effect of multivalent metal cations, including vanadium(V) and tin (Sn), on the electrical properties of vanadium-doped zinc tin oxide (VZTO) was investigated in the context of the fabrication of thin-film transistors (TFTs) using a single VZTO film and VZTO/ZTO bilayer as channel layers. The single VZTO TFT did not show any response to the gate voltage (insulator-like behavior). On the other hand, the VZTO/ZTO bilayer TFT exhibited a typical TFT transfer characteristic (semiconducting behavior). X-ray photoelectron spectroscopy revealed that, in contrast to what is commonly true in many oxides, oxygen vacancies (V(O)) in VZTO did not provide a dominant contribution to the total carrier concentration, because the V(O) peak area in the single VZTO film was 5.4% and reduced to 4.5% in VZTO/ZTO bilayer. Instead, Sn 3d5/2 and V 2p3/2 spectra suggest that the significant reduction in Sn and V ions is strongly related to the insulator-like behavior of the VZTO film. In negative-bias illumination tests and illumination tests with various photon energies, the VZTO/ZTO bilayer TFT had much better stability than the ZTO TFT. This result is attributed to the reduction of donor-like states ([Formula: see text]O) that can be positively ionized by blue and green illumination.
authors.affiliation: School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon, 440-746, Korea.
authors.forename: Myeong Gu
authors.initials: MG
authors.lastname: Yun
authors.affiliation: School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon, 440-746, Korea.
authors.forename: Cheol Hyoun
authors.initials: CH
authors.lastname: Ahn
authors.affiliation: School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon, 440-746, Korea.
authors.forename: Sung Woon
authors.initials: SW
authors.lastname: Cho
authors.affiliation: School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon, 440-746, Korea.
authors.forename: So Hee
authors.initials: SH
authors.lastname: Kim
authors.affiliation: School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon, 440-746, Korea.
authors.forename: Ye Kyun
authors.initials: YK
authors.lastname: Kim
authors.affiliation: School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon, 440-746, Korea.
authors.forename: Hyung Koun
authors.initials: HK
authors.lastname: Cho
keywords: dual electrical property; multivalent metal cation; oxide semiconductor; stability; thin film transistor