Unravelling processing issues of nanowire-based solar cell arrays by use of electron beam induced current measurements

Abstract

III-V vertical nanowire arrays have great potential for next generation photovoltaics. Development towards high performing nanowire solar cells, which consist of a parallel connection of millions of single nanowire solar cells, requires a fast characterization technique that establishes a link between device performance and device processing. In this work, we use electron beam induced current measurements to characterize fully processed InP nanowire array solar cells at the nanoscale. Non-functional areas on fully processed devices can be quickly identified and processing induced effects on device performance can be clearly distinguished from those arising from nanowire growth. We identify how limiting factors on device performance are related to the processing procedures and provide a path to improve device performance further. In this way, electron beam induced current measurements become an essential tool for nanowire solar cell efficiency optimization, providing fast and useful information at the nanoscale and thus enabling up-scaling of the technology.