Solution-Process ZnO-Mediated Semiconductor Bonding for Photovoltaic Applications

Abstract

Semiconductor wafer bonding mediated by a transparent conductive oxide, ZnO, prepared by a handy, low-cost solution spin-on process, has been demonstrated. Our successful ZnO-mediated bonds exhibit high mechanical strength (> 0.1 MPa), optical transparency (> 90%), electrical conductivity (0.15 Ω cm2), and roughness tolerance. Our bonding scheme can be a versatile alternative low-cost fabrication process for highefficiency lattice-mismatched multijunction solar cells, with no need of cleanroom environment in contrast to the conventional direct bonding.