Three‐junction monolithic interconnected modules for concentrator photovoltaics

Abstract

A core issue in concentrator photovoltaic technology (CPV) is the resistive losses in cells that usually limits the maximum photoconversion efficiency under high concentration. We propose the use of three‐junction monolithic interconnected modules (MIM) to mitigate resistive losses by providing high‐voltage low‐current power. First, we present the fabrication of InGaP/InGaAs/Ge front‐contacted microcells with various designs and dimensions. Front‐contacted cells are the key enabler for the MIM fabrication and demonstrate good electrical characteristics under one sun, similar to standard‐contacted cells. The base front contact size is minimized to limit the unutilized area on the wafer. Second, fabrication techniques for interconnecting cells in MIM are described. Finally, electrical measurements show a record conversion efficiency of 35.1% under 798 suns for the first three‐junction MIM reported (17.8% when considering the entire device area). Versatility and further optimization of the devices are discussed to enlarge their field of application.

High‐Efficiency GaAs Solar Cells Grown on Porous Germanium Substrate with PEELER Technology

“…The main steps include the creation of a mesa structure down to the GaAs buffer [ 17 ] using low‐damage plasma etching (a similar design reported in ref. [18]) and electrode metal depositions. The lift‐off evaporation process for the creation of these metallic contacts has been executed by the association of different procedures.…”