Fabrication and characterization of printed phototransistors based on monochalcogenide inks

Two-dimensional (2D) layered semiconductors of Group-III monochalcogenides have gained increasing attention in photonics and electronics. The fabrication of large-scale, inexpensive inks which can be used in printed electronics applications is facilitated by the solution processing of 2D materials. In this study, gallium sulfide (GaS)-, gallium selenide (GaSe)-, and gallium telluride (GaTe)-loaded inks were synthesized and implemented to fabricate phototransistors on SiO2\Si substrates. To explore the printed device performances, several color illuminations were applied to the printed phototransistor, and the mobility, photoresponsivity, and external quantum efficiency parameters were compared. Under red-light illumination, the mobility of a GaTe nanoparticle-based phototransistor reached 7.456 cm2 V-1 s-1. The responsivity of the GaTe-based phototransistor was found to be the highest, with the value of 9.52 A W-1 under green light illumination. However, GaSe-based phototransistors gave the highest EQE value of 2482 (%) under blue light illumination with the mobility of 7.04 cm2 V-1 s-1. This study demonstrates that printable Group-III monochalcogenide inks can be synthesized with desired properties for use in printed electronic applications.