Improvement of device performance and instability of tungsten-doped InZnO thin-film transistor with respect to doping concentration

Abstract

W-doped InZnO (WIZO) thin-film transistors (TFTs) were fabricated by co-sputtering with different W doping concentrations. We varied the W doping concentration to change the device performance and stability of the WIZO TFTs. WIZO TFTs with a W doping concentration of ∼1.1% showed the lowest threshold voltage shift and hysteresis. We correlated the device characteristics with the evolution of the electronic structure, such as band alignment, chemical bonding states, and band edge states. As the W doping concentration increased, the oxygen-deficient bonding states and W suboxidation states decreased, while the conduction-band offset and the incorporation of the WO x electronic structure into the conduction band increased.

Enhancement of the Device Performance and the Stability with a Homojunction-structured Tungsten Indium Zinc Oxide Thin Film Transistor

“…Here, the decrement of carrier concentration is strongly associated with a decrement of the oxygen deficiency state caused by increase of doping concentration of tungsten with high oxygen bond dissociation energy. In addition, the parabolic trend of hall mobility with increasing tungsten doping concentration is resulted from the changes of electronic structure by incorporation of excess tungsten atoms, provided in the previous study 23 . At the same time, the conducting WIZO layer according to tungsten-doping concentration was formed as the S/D electrode layer on the optimized WIZO active-channel layer for evaluation of electrical characteristics of the TFT device.…”

“…eTo minimize variability of process conditions and contamination on the target surface, film deposition was started after a pre-clean sputtering of the target for 15 minutes. RF-power values of the WO 3 and the InZnO target for established optimum concentration of the tungsten doping from a previous study were fixed at 10 W and 150 W, respectively, and the WIZO active-layer thickness is 10 nm 23 . Process pressure and relative oxygen-flow rate were set as 5 mTorr and the O 2 /(Ar + O 2 ) ratio was 0.05, respectively.…”

Effects of Embedded TiO2−x Nanoparticles on Triboelectric Nanogenerator Performance

“…For the detailed analysis of chemical bonding states, the O 1 s spectra were carefully normalized and de-convoluted with three different Gaussian peaks as indexed with O1, O2, and O3 centered at 530.9 eV, 531.8 eV, and 532.9 eV, respectively. Each of the representatively assigned peaks from a low binding energy is related to the oxygen state in the metal-oxide lattices, the oxygen-deficient state, and chemisorbed or dissociated oxygen states, or OH − impurities, respectively [ 14 , 15 ]. Among them, the relative area of the oxygen-deficient peak (O2) is dramatically increased from 18.80% to 24.63% after TiO 2−x NPs embedding, which is remarkable.…”

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.…”