Development of a Vertical Geometry based amorphous selenium novel photodetector with the use of a VUV transparent window.

In this work, we investigate ongoing efforts to develop a modified wet-transfer technique for applying graphene as the top electrode on an amorphous selenium (a-Se)–based photodetector. Trivial Transfer Graphene was initially used with varying degrees of success. Because a-Se is a highly sensitive material, proper cleaning of the PMMA layer on top of the graphene is critical. However, common methods such as heating the sample or prolonged submersion in acetone can induce crystallization of the a-Se or cause delamination from the bottom electrode. Our first approach involved using multilayer graphene (50L) grown on a nickel substrate, which eliminates the need for a PMMA support layer; this method yielded successful transfers. Our second approach used 10L graphene on copper, where we optimized the PMMA thickness to allow for clean removal under conditions safe for the underlying a-Se. In this poster, we also present our voltage- and temperature-dependent measurements, along with optical transmission studies across various wavelengths of interest.