We report the fabrication and characteristics of a ZnO thin-film transistor (TFT) using a 50 nm thick ZnO film as an active layer on an Al 2 O 3 gate dielectric film deposited by atomic layer deposition. Lowering the deposition temperature allowed the control of the carrier concentration of the active channel layer (ZnO film) in the TFT device. The ZnO TFT fabricated at 110 • C exhibited high-performance TFT characteristics including a saturation field-effect mobility of 11.86 cm 2 V −1 s −1 , an on-to-off current ratio of 3.09 × 10 7 and a sub-threshold gate-voltage swing of 0.72 V decade −1 .

Mechanically driven light emission from particles embedded in elastomer films has recently attracted interest as a strong candidate for next-generation light sources on display devices because it is nondestructive, reproducible, real-time, environmentally friendly, and reliable. The origin of mechanoluminescence (ML) obtained from particles embedded in elastomer films have been proposed as the trapping of drifting charge carriers in the presence of a piezoelectric field. However, in this study, we propose a new origin of ML through the study of the microstructure of a Cu-doped ZnS particles embedded in an elastomer composite film with high brightness using transmission electron microscopy (TEM) to clearly demonstrate the origin of ML with respect to the microstructure of ML composite films. The TEM characterization of the ML composite film demonstrated that the Cu-doped ZnS particles were fully encapsulated by a 500 nm thick Al layer, which acts as an electron source for ML emission. Furthermore, we fabricated a flexible electro-mechanoluminescence (EML) device using a Cu-doped ZnS particles embedded in a flexible elastomer composite film. Our research results on a new emission mechanism for ML and its application in flexible light generating elastomer films represent an important step toward environmentally benign and ecofriendly flexible electro-mechanoluminescent lighting devices.

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This study reports the design growth and characterization of quaternary Mg and Ga codoped ZnO (MGZO) thin films with transparent conductive characteristics deposited on glass substrates by RF magnetron sputtering. The effects of the Ga concentration (from 0 to 2 at %) on the structural, chemical, morphological, optical, and electrical properties of MGZO thin films were investigated. X-ray diffraction study showed that all the MGZO thin films were grown as a polycrystalline hexagonal wurtzite phase with a c-axis preferred orientation and random in-plane orientation. The 2θ value of the (0002) peak of MGZO thin films decreased with increasing Ga concentration. X-ray photoelectron spectroscopy confirmed the Mg and Ga binding energy peaks from the MGZO thin films. The MGZO thin films had a smoother surface morphology. The optical study showed that the band gap energy of MGZO thin films systematically increased from 3.25 to 3.75 eV with increase Ga concentration. The electrical resistivity of the MGZO thin films was improved from 9.5 × 10–2 to 6.89 × 10–4 Ω cm with increasing Ga concentration.

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