Fig. 3
From: Active bialkali photocathodes on free-standing graphene substrates

a QE spectral response, b Optical transmission, c Stability of K2CsSb PCs deposited on graphene substrates. For a and b, red circles and black squares are for the PCs on 5 and 8-layer graphene substrates, respectively. Purple arrows indicate the regions with signature features. Black line in c is for a PC on SS substrate as a reference, and purple line is for PC on 8-layer graphene substrate. QE is normalized in c to the PC on SS substrate