Fig. 4: Role of oxygen vacancy defects in mediating VRH transport.
From: Large mobility modulation in ultrathin amorphous titanium oxide transistors
a Transfer characteristics of the TiOx TFT (W/L = 500 µm/5 µm) fabricated using ultrathin TiOx film annealed in oxygen atmosphere (15 min at 400 °C followed by 15 min at 600 °C); b µFE variation with Vg with power law fits for Vg > 50 V and Vg < 50 V. The exponent values of 1.85 and 3.28 indicate that the carrier transport occurs via VRH. The decrease in the number of available defects states however restricts the charge mobility. c Transfer characteristics of the TiOx TFT (W/L = 500 µm/5 µm) fabricated using forming gas annealing and the PMMA top-coat, leading to the passivation of surface defects and, consequently, a small increase in the on-state current due to decreased carrier scattering. d µFE variation with gate voltage and power law fit for Vg > 40 V and Vg < 40 V with the exponents of 0.79 and 2.99 indicating the VRH transport at low Vg changing toward TLC transport at high Vg.
