Transient Current Response for ZnO Nanorod‐Based Doubly Transparent UV Sensor Fabricated on Flexible Substrate

Abstract

We present the transient current response for a ZnO nanorod‐based doubly transparent UV sensor. ZnO nanorods (ZNRs) are sandwiched between indium tin oxide (ITO) electrodes to make the device doubly transparent on a flexible polyethylene terephthalate (PET) substrate. The average ZNR length and diameter are 1.7 μm and 62 nm, respectively, and the ITO is perfectly sputtered upon ZNR surface. All the ZNRs are c‐axis oriented perpendicular to the substrate with a typical hexagonal wurtzite ZnO structure. Photoluminescence spectra show a typical high‐intensity peak near 375 nm and a broad peak in the visible region. UV sensing is confirmed by testing ZNR current–voltage characteristics and transient current response under UV on–off conditions for straight and inflexed ZNRs. The sensor shows a 2.3 times increase in current intensity under UV illumination at 4 V. The transient current shows a typical sinusoidal wave‐like response with three prominent regions under constant voltage supply. The recovery time is almost five‐times of the response time, which confirms the five‐times faster boundary hole trapping in the sensor than their release on the flexible substrate. Also, the current intensity decreases for an unilluminated flexed device and increases for an UV‐illuminated flexed device because of strain‐induced ZNR piezotronic effects under flexible deformation.

Hybrid ZnO Flowers-Rods Nanostructure for Improved Photodetection Compared to Standalone Flowers and Rods

“…Similarly, as soon as the UV was turne the HZFR device recovered very quickly when compared to the NR and NF sensors like the active devices, which provide power gain to the current response of the de the presented devices are passive devices, that do not provide a power gain to the ou current. Provided the passive nature of the devices, the response and recovery tim haviors of the devices are comparably better than those in recently published re [12,19].…”

“…ZnO strategically lies at the borderline of inorganic and organic chemical compounds, which makes it a very important compound for sensor applications, due to its intertwined chemical and optical properties [10,11]. Notwithstanding, the more pronounced surface oxygen chemisorption process at ambient conditions makes it one of the best candidates for UV and gas sensor applications [12,13]. Moreover, the visible blind intrinsic habit and very high absorption in the UV band provide a great impetus to ZnO-based UV sensors [14].…”

Low-Temperature Fabrication of High-Performance and Stable GZO/Ag/GZO Multilayer Structures for Transparent Electrode Applications

“…Transparent electrodes (i.e., thin films based on transparent conductive (TC) materials) are some of the most important parts of many optoelectronic devices, such as touch panels, organic light-emitting diodes (OLEDs), optical sensors, and solar cells [1][2][3][4][5].…”

Intrinsic Control in Defects Density for Improved ZnO Nanorod-Based UV Sensor Performance

“…ZnO is known for multidisciplinary sensor applications because of its strategic location on the borderline of organic and inorganic compounds [17,18]. Most importantly, it has potential applications in photodetectors and UV sensors because of the surface chemisorbed oxygen species and high level absorption in the UV band [19,20]. Photodetector applications require fast response and recovery times, large on/off ratios, and high photo responsivity [21].…”