Enhancing the performance of tungsten doped InZnO thin film transistors via sequential ambient annealing

Abstract

This study suggests a sequential ambient annealing process as an excellent post-treatment method to enhance the device performance and stability of W (tungsten) doped InZnO thin film transistors (WIZO-TFTs). Sequential ambient annealing at 250 °C significantly enhanced the device performance and stability of WIZO-TFTs, compared with other post-treatment methods, such as air ambient annealing and vacuum ambient annealing at 250 °C. To understand the enhanced device performance and stability of WIZO-TFT with sequential ambient annealing, we investigate the correlations between device performance and stability and electronic structures, such as band alignment, a feature of the conduction band, and band edge states below the conduction band. The enhanced performance of WIZO-TFTs with sequential ambient annealing is related to the modification of the electronic structure. In addition, the dominant mechanism responsible for the enhanced device performance and stability of WIZO-TFTs is considered to be a change in the shallow-level and deep-level band edge states below the conduction band.

Improved Performance and Operational Stability of Solution-Processed InGaSnO (IGTO) Thin Film Transistors by the Formation of Sn–O Complexes

“…Thus, the band edge states were resolved into shallow band edge states (D1) and deep band edge states (D2), which are located near the conduction band edge and relatively far from the conduction band edge, respectively. The shallow band edge state (D1) is related to the charge transport and carrier concentration by oxygen vacancies, while the deep band edge state (D2) is related to the trapping and scattering of carriers. ,, The area ratio of each band edge peak was also calculated to compare the difference of electrical characteristics. As the molar ratio of Ga in IGTO thin films increased, the calculated area ratio of shallow band edge state (D1) decreased significantly.…”

“…The shallow band edge state (D1) is related to the charge transport and carrier concentration by oxygen vacancies, while the deep band edge state (D2) is related to the trapping and scattering of carriers. 18,48,49 The area ratio of each band edge peak was also calculated to compare the difference of electrical characteristics. As the molar ratio of Ga in IGTO thin films increased, the calculated area ratio of shallow band edge state (D1) decreased significantly.…”

Tungsten-Doped Zinc Oxide and Indium–Zinc Oxide Films as High-Performance Electron-Transport Layers in N–I–P Perovskite Solar Cells

“…The N-I-P device structures fabricated with metal oxide ETLs produced PCEs of up to 16.44%. To the best of our knowledge, this constitutes the highest performance yet reported for devices based on W oxides and demonstrates the great potential of this new material as ETLs for PSCs and for other potential applications [42,43].…”

“…The composition of metal oxide semiconductors can be used to control the electrical characteristics and additionally, for metal oxide films deposited under a partial vacuum, the oxygen partial pressure in the deposition process can be used to control the composition and properties of films [33][34][35]. Zinc-oxynitride (ZnON) [36,37], Zinc oxide (ZnO) [38,39], Indium-zinc oxide (IZO) [40,41], and W-doped indium-zinc oxide (WIZO) [42,43], for example, are metal oxide semiconductors which have been investigated as channel materials for thin-film field-effect transistors in display backplanes and other optoelectronic devices due to their high transparency, high mobility, and high conductivity. Notably, the element W in WIZO thin films can be used to control the electronic structure, including the band alignment, oxygen-deficient bonding states, and band edge states below the conduction band.…”