Uncertainty in photoluminescence-based effective carrier lifetime measurements

Photoluminescence-based effective carrier lifetime measurements have received increased attention in recent years due to their high sensitivity, even at very low excess carrier concentration. Like any other measurement technique, knowledge regarding the experimental uncertainty is crucial in order to distinguish significant differences between samples. However, until now, the uncertainty of the photoluminescence based measurements has not been comprehensively analysed. This paper presents a preliminary study of the uncertainty associated with photoluminescence based lifetime measurements. The uncertainty of both the excess carrier concentration and the effective carrier lifetime is expressed by the uncertainty of the input parameters, such as calibration constants, bulk dopant concentration, wafer thickness and front surface reflection. The paper illustrates the importance of accurate determination of the calibration constant A_i and bulk resistivity in order to reduce the measurement uncertainty.