Fully Printed GaTe Based Photodetector on PET Substrate

Layered III-VI monochalcogenides such as gallium telluride (GaTe) and indium selenide (InSe) have positioned themselves for high-performance optoelectronics including radiation detectors and solar cells due to the optimum band gap as a solar window material and as semi-insulating at room temperature [1]. The unique crystal structure of GaTe induces interesting consequences on the band structure and hence the optical and electronic characteristics, such as direct band gap and strong excitonic absorption [2]. However, the fabrication of the photo detectors using these materials on flexible substrates employing printing technologies owing to the cost effective, fast, and easy production properties is of keen interest. In this work, we utilize screen printing and slide dye coating technologies to fabricate a photodetector based on solution-processed GaTe on PET sheets. To do this, PET substrate is respectively cleaned in acetone, iso-propanol, and distilled water by using ultrasonic sonicator and dried using $\mathrm{N}_{2}$ . After that, silver (Ag) nanoparticle-based ink is used to screen-print the interdigit for top contacts as shown in Fig. 1(a). Then, for sintering a heating oven is used at 120°C for 10 min. In order to change hydrophobicity, surface treatment is done using ozone plasma for 5 min. Also, GaTe ink is prepared using liquid phase exfoliation (LPE) method [2]. To do this, 10 mg of GaTe is immersed into iso-propanol and sonicated for 45 min. utilizing ultrasound sonicator followed by slide dye coating to print GaTe layer with 60 passes, see Fig. 1(b).