Vanadium dioxide (VO₂) has drawn significant attention due to a unique band-structure and multifaceted optoelectronic properties. However, VO₂-based photodetectors reported till date involve complex structures and/or constrained wavelength response. Moreover, there is limited understanding of parameters which control the insulator-to-metal transition (IMT) and photoresponse in VO₂. In this work, we present VO₂ based two-terminal planar devices and explore the size-dependency of IMT and photoresponse in VO₂ devices. We investigate the photoresponse of VO₂ devices at a broadband range from ultra-violet to near infrared at three temperature regions: room temperature, IMT slope, and beyond IMT slope. We further postulate the mechanism for photoresponse at all three temperature regions. A significant enhancement in photoresponse and figure of merit of photodetectors is achieved beyond IMT slope region. An intermediate state driven by deep level defects assists the broadband photoresponse which is supported by cathodoluminescence (CL) analysis. The ability to manipulate the IMT and the broadband photoresponse opens opportunities for designing and controlling functional domains of VO₂ for scalable micro- and nano-scale devices and sensor applications.

由于独特的能带结构和多方面的光电特性，二氧化钒（VO ₂）已引起了广泛的关注。然而，迄今为止报道的基于VO ₂的光电探测器涉及复杂的结构和/或受约束的波长响应。此外，对控制VO _2中的绝缘体到金属的过渡（IMT）和光响应的参数的了解有限。在这项工作中，我们介绍基于VO ₂的两端子平面器件，并探讨VO ₂器件中IMT和光响应的尺寸依赖性。我们研究VO ₂的光响应在三个温度区域：室温，IMT斜率和IMT斜率之外，宽带设备的范围从紫外线到近红外。我们进一步假设了在所有三个温度区域的光响应机制。在IMT斜率区域以外，可以显着提高光电探测器的光响应和品质因数。由深层缺陷驱动的中间状态有助于宽带光响应，这由阴极发光（CL）分析支持。操纵IMT和宽带光响应的能力为设计和控制VO _2的功能域提供了机会，以用于可扩展的微米和纳米级设备以及传感器应用。