Work function tunable laser induced graphene electrodes for Schottky type solar-blind photodetectors

Abstract

Laser-induced graphene (LIG) is a simple, environmentally friendly, efficient, and less costly method, as well as can form various shapes on a flexible substrate in situ without the use of masks. More importantly, it can tune the work function of LIG easily by changing laser parameters to control the transportation of carriers. In this work, the work functions of LIG were controlled by adjusting the frequency or speed of the laser, and a series of LIG/GaOx Schottky photodetectors were formed. When the work function of the graphene increases, the Fermi energy is shifted below the crossing point of the Π and Π* bands, and then more electrons or holes can be activated to participate in the conduction process, resulting in low resistance. Meanwhile, a large built-in electric field can be formed when using a high work function LIG, which is more beneficial to separate photo-generated carriers. Enabled by the controllable LIG, LIG/GaOx Schottky photodetectors can be modulated to have high photoresponsivity or self-powered characteristics. Our work provides a high-performance photodetector with excellent mechanical flexibility and long-life stability, promising applications in the flexible optoelectronic fields.