Open-circuit voltage quantum efficiency technique for defect spectroscopy in semiconductors

摘要

The temperature-dependent quantum efficiency of the open-circuit voltage is introduced for defect characterization in semiconductors. This technique measures the spectral response of the open-circuit voltage of a diode at different temperatures. The diffusion length is extracted from the spectral photovoltage and converted into carrier lifetime. This results in temperature-dependent lifetime curves that can be analyzed with the Shockley-Read-Hall model. The method allows defect analysis to be performed as soon as a junction is formed in the device and is also applicable to solar cells and Schottky diodes. The determination of the lifetime via the spectral response avoids trapping effects that commonly hamper other lifetime spectroscopy techniques. Examples of the application of the technique are given, showing good agreement with the temperature-dependent quantum efficiency of the short-circuit current. The results are consistent with temperature-dependent lifetime spectroscopy reported in the literature.