Quantitative carrier lifetime measurement with micron resolution

Abstract

In the last fifteen years the measurement of the spatially resolved carrier lifetime has emerged as a valuable tool for the characterization of silicon wafers and solar cells. In most of the available measurement methods, the spatial resolution is constrained to the order of several 10 to 100 μm by the diffusion length of the charge carriers. In this paper we introduce a contactless quantitative technique to determine the Shockley–Read–Hall lifetime with a spatial resolution of 1 μm. This technique is based on high injection microphotoluminescence spectroscopy and allows a quantitative analysis of microscopic defects such as grain boundaries and metal precipitates by virtue of the high spatial resolution.