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氧化物半导体柔性电子学研究进展

Flexible electronics and devices based on oxide semiconductors

  • 摘要: 柔性电子学器件在未来消费电子领域有巨大的应用前景,更是消费升级和社会进步的必然需求,在可穿戴传感、柔性显示、电子皮肤和可植入医疗等领域有着广泛的应用前景。柔性透明高压二极管器件在构建一体化光伏系统和自供电可穿戴设备的能源管理电路中有着巨大的应用潜力。文章首先设计并制作了一种新颖的柔性透明ZnO场效应二极管,其整流比可高达108,漏电流低至10-15 A/μm,且制备工艺和普通TFT完全兼容。通过引入特定尺寸的错排(offset)区域,进一步制备了击穿电压最高可达150 V的柔性透明高压二极管;利用4个单元器件组合成柔性高压全波整流电路,成功地将摩擦纳米发电机产生的高压交流电整流为直流电,存储到超级电容器中。柔性光电探测器因具有轻便耐用、柔软便携、可与非平面组织贴合等独特优势,逐渐成为光电探测技术发展的一个新方向。通过微量调控生长过程中的氧流量,系统研究了柔性非晶Ga2O3日盲紫外探测器和X射线探测器的性能与材料制备过程中氧分压的对应关系,实现了对器件响应度和响应速度的调控,并给出了相应的物理模型;通过器件结构的设计与材料物性的调控,器件的性能得到了大幅提升,并显示出良好的耐高压、耐辐照和弯曲特性。

     

    Abstract: Flexible electronics has advanced at a rapid pace in the past dozen years, driving a fascinating transformation of the pattern of consumer electronics. Building integrated photovoltaic and self-powered wearable electronics are two related research fields which promise light weight and high integration devices that do not need external electrical connection. Recent studies have explored the emerging applications of high-voltage thin film transistors (HV-TFTs) and high-voltage thin film diodes (HV-TFDs) in energy management circuits for the above-mentioned applications. We have recently constructed flexible and fully transparent fieldeffect diodes (FEDs) with a high rectification ratio (~5×108) and low leakage current (~10-15 A/μm). Different from other junction diodes, ours utilize a novel diode- connected TFT architecture, and the field effect plays an important role in the operation. Furthermore, by adopting an offset structure in the FED architecture, the diodes are able to withstand a reverse voltage as high as 150 V; the high AC voltage generated by the triboelectric nanogenerator is rectified into a DC voltage through full-wave rectifier circuits composed of four HVTFDs, then successfully charged into supercapacitors. As building blocks, large-area, low-cost and light weight flexible photodetectors are becoming increasingly important for various flexible device platforms. This new type of detector is not only portable and cost-effective but also readily shaped to fit non-planar surfaces. We developed a fine oxygen-flux controlling technique, and fabricated flexible solar-blind UV and X-ray detectors based on amorphous Ga2O3 film sputtered at room temperature. A study of the photoresponse characteristics under UV/X-ray illumination combined with density functional theory calculations indicates that the photocurrent and response decay time strongly depend on the oxygen partial pressure, i.e., oxygen vacancy (Vo) states. Notably, an enhanced X- ray photocurrent is observed and ascribed to the slow-down annihilation rate caused by the neutralization of more ionized Vo states. Flexibility and fatigue tests show no obvious degradation of the device performance under UV and X-ray irradiation, demonstrating the robustness of our photodetectors.

     

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