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Channel shape dependency on device instability for amorphous indium–gallium–zinc oxide (a-IGZO) thin film transistors (TFTs) is investigated by using various channel shape devices along with systematic electrical characterization including DC I-V characeristics and bias temperature stress tests. a-IGZO TFTs with various channel shapes such as zigzag, circular, and U-type channels are implemented and their vertical and lateral electric field stress (E-field) effects are systematically tested and analyzed by using an experimental and modeling study. Source and drain (S/D) electrode asymmetry and vertical E-field effects on device instability are neglibible, whereas the lateral E-field effects significantly affect device instability, particularly for zigzag channel shape, compared to circular and U-type TFTs. Moreover, charge trapping time (τ) for zigzag-type a-IGZO TFTs is extracted as 3.8 × 104, which is at least three-times smaller than those of other channel-type a-IGZO TFTs, hinting that local E-field enhancement can critically affect the device reliability. The Technology Computer Aided Design (TCAD) simulation results reveal the locally enhanced E-field at both corner region in the channel in a quantitative mode and its correlation with hemisphere radius (ρ) values.

Multi-layered MoS 2 inverters with light shielding (LS) layers were fabricated and demonstrated for application in highly sensitive photo detectors, exploiting the particular advantages of an atomically thin layer and a sizable electrical band gap. The photoleakage behaviors of the inverters under changing wavelengths of light were experimentally demonstrated to occur in a controlled manner, and were analytically validated by load-line analysis. When the inverters were operated with a depletion load in the light of blue light emitting diodes (LEDs), the low noise margin (NML) and transition width were significantly enhanced, by approximately 20 and 220%, respectively, as compared to those of the inverters in the dark.