Lateral electron transport in Cu(In,Ga)Se2 investigated by electro-assisted scanning tunneling microscopy

Abstract
We investigate the lateral electron transport across grain boundaries in Cu ( In , Ga ) Se 2 (CIGS) by a combination of scanning tunneling microscopy(STM) with the excitation provided by the electron beam in electron microscopy—or electro-assistedSTM. Using this method, we report evidence for a significant barrier for electron diffusion across grain boundaries in Cu Ga Se 2 (CGS), which is not present in Cu In Se 2 (CIS). Finally, we discuss the effects of gallium addition.