Accurate determination of minority carrier mobility in silicon from quasi-steady-state photoluminescence

Abstract

Minority carrier mobility is a crucial transport property affecting the performance of semiconductor devices such as solar cells. Compensation of dopant species and novel multicrystalline materials call for accurate knowledge of minority carrier mobility for device simulation and characterization. Yet, measurement techniques of minority carrier mobility are scarce, and published data scatter significantly even on monocrystalline material. In this paper, the determination of minority carrier mobility from self-consistent quasi-steady-state photoluminescence measurements of effective carrier lifetime is presented. The measurement design is distinguished by a limitation of carrier recombination through minority carrier transport—with excess carrier generation and recombination confined to opposite interfaces, respectively. Minority carrier mobility is inferred from the minority carrier diffusion coefficient via the Einstein relation. An experimental proof of concept on monocrystalline p-type material is provided, showing good agreement with state-of-the-art data and models. Considerations for the applicability of the method to compensated and multicrystalline silicon materials are discussed.