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Deep ultraviolet (UV) photodetectors have wide applications both in civil and military fields. Many materials have been explored to realize deep UV photodetection. Amorphous gallium oxide (a‐GaOx), as a member of transparent amorphous oxide semiconductors (TAOSs), has attracted a great deal of attention due to its ultrawide bandgap and scalable synthesis at room temperature. Plenty of researches have been focused on this topic in recent years. Herein, the latest progresses in the preparation methods of a‐GaOx using radio‐frequency sputtering, pulsed laser deposition, atomic layer deposition, and other deposition techniques are summarized. Dependence of the stoichiometry, crystallinity, optical, electrical, and morphological properties on different preparation parameters and doping/alloying elements is tentatively discussed, as well as those deep UV photodetectors based on a‐GaOx and related thin films. Finally, a short summary with further possible investigations is provided for a better understanding and development of a‐GaOx materials and photodetectors. [ABSTRACT FROM AUTHOR]

In this paper, we report the fabrication of flexible and transparent InGaZnO thin-film transistors on muscovite mica substrates. The mica substrate is compatible with four-step photolithographic processes as well as high-temperature processes. The field-effect mobility, subthreshold swing, ON/OFF ratio, threshold voltage, and hysteresis voltage are improved after annealing both at 300° C and 400° C in nitrogen. The device demonstrates more stable performance under positive gate bias stress when annealed at 400° C than at 300° C. The electrical performances are stable when exposed to tensile bending cycles up to 10 000 times. The mica with devices shows small optical loss in the visible region, where the average transmittance is as high as 86.75%. [ABSTRACT FROM AUTHOR]

In this paper, we report the fabrication of flexible ZnO thin-film transistors (TFTs) on the 25- $\mu \text{m}$ -thick copper substrate. The Cu substrate compatible with high-temperature processes was deposited by electroplating, which led to a smooth surface. The ZnO layer was deposited at room temperature, and a thermal annealing process was conducted at 300 °C in the air after the fabrication of TFTs. The threshold voltage, hysteresis voltage, and contact resistance are improved after annealing, whereas the mobility, subthreshold swing, and ON/OFF ratio are barely changed. The stabilities of ZnO TFTs are also enhanced, evidenced by the smaller threshold voltage shifts induced by positive and negative gate bias stresses. The field-effect mobility, threshold voltage, and subthreshold swing are stable even when exposed to a mechanical tensile strain up to 1.25% and 10 000 bending cycles. [ABSTRACT FROM AUTHOR]

This work reports flexible fully transparent high-voltage diodes that feature high rectification ratio ( R r ~ 10 8 ) and high breakdown voltage ( V b ~ 150 V) simultaneously, combined with their applications as building blocks of energy management systems in wearable electronics where triboelectric nanogenerators (TENGs) are used as power source. Both experimental results and technology computer aided design (TCAD) simulations suggest that R r and V b can be modulated by the offset length in an opposite tendency. The low reverse leakage current (~ 10 –15 A/μm) guarantees an ultra-low power consumption in standby mode, which is a core issue in wearable device applications. Besides the unprecedented electrical performance, the diodes exhibit good mechanical robustness with minimal degradation throughout the strain and fatigue tests. By incorporating these high-voltage diodes into half-wave and full-wave rectifier circuits, the high alternating current (AC) output voltage of TENGs is successfully rectified into direct current (DC) voltage and charged into supercapacitors (SCs), indicating their high integration and compatibility with TENGs, and thus their promising applications in various wearable electronic systems. [ABSTRACT FROM AUTHOR]

[Display omitted] • PDMS surface is wrinkled by using an rf-sputtered ZnO sacrificial layer. • The optimal power density of wrinkle TENG increases by 78.5 times than the flat one. • The simulation proves the wrinkled surface can promote TENGs' output performance. Triboelectric nanogenerators (TENG) can convert mechanical energy to electricity. Its conversion efficiency strongly depends on the contact area of the triboelectric materials. Here, a simple strategy is developed to wrinkle the surface of polydimethylsiloxane (PDMS) by using an rf-sputtered ZnO sacrificial layer. The resulting TENG device demonstrates improved triboelectric performance in contrast to its counterpart fabricated on a flat PDMS. The optimal open circuit voltage (V OC), short circuit current (I SC) and pulse output power density with matched external load are 170 V, 8.7 × 10-7 A and 189 μW/cm2, which are 8.9, 2.2 and 78.5 times higher than those of the flat device, respectively. This simple and efficient method may hopefully promote the application of TENG in the field of flexible wearable electronics. [ABSTRACT FROM AUTHOR]

Abstract We report the realization of flexible fully-transparent high-voltage (HV) inverters composed with a high-voltage thin film transistor (HVTFT) drive and an on-chip high-voltage thin film diode (HVTFD) load. The overall fabrication temperatures are decreased as low as 75 °C to minimize the built-in strain caused by the large thermal expansion mismatch. High on/off ratio of 1010, rectification ratio of 109 and voltage gain of 8.5 are achieved in the flexible HVTFT, HVTFD and HV inverter, respectively. In addition, the flexible HV devices are fabricated with a novel self-aligned photolithography technology, and the fabrication procedure and working principle are depicted in this letter. This work combines HV electronics with the upsurging flexible transparent electronics, and will initiate interdisciplinary researches between the two fields. Graphical abstract Unlabelled Image Highlights • A self-aligned photolithography process is presented. • The mechanism of the process is studied with TCAD simulation. • High performance high-voltage devices are achieved with this process. [ABSTRACT FROM AUTHOR]