IGZO Based Oxide Heterostructured Phototransistor for Widening The Detection Limit up to 1000 nm Wavelength

On the rapidly developing technologies for light communication, night vision system, invisible security system, and health care system industries, detecting near infrared (NIR) wavelength light is becoming a crucial component for electronic devices. Among various structures of photodetectors, such as phototransistors, photodiodes, and photoresistors, phototransistors possess much higher potential compared to other structures photodetectors, such as ultra-low dark current, facile tunable photocurrent by modulating gate and drain bias, which leads to the much higher photodetection characteristics. Numerous materials, such as organic semiconductors (OSCs), quantum dots(QDs), or perovskite materials have widely investigated for transparent NIR detection owing to their adequate photon-electron conversion efficiency maintaining relatively high transparency. However, these materials are intrinsically suffered from environmental moisture or oxygen, which leads to the accelerated degradation of the device. Here, to avoid the above issues, oxide phototransistor with IGZO/Ag₂O was fabricated for the detection of NIR wavelength light. The detectable wavelength range of IGZO phototransistor was highly enlarged from ultraviolet(UV)-visible (vis, 450 nm) to UV-vis-NIR(1000 nm). The device exhibited high photoresponsivity and photodetectivity characteristics of 9.9 A/W and 5.55×10¹⁴ Jones, respectively. Our results suggest a useful method for fabricating metal oxide hetero-structured NIR phototransistors.