System for high accuracy internal quantum efficiency measurement

We developed a system that evaluates simultaneously the spectral dependence of quantum efficiency (QE) and internal quantum efficiency (IQE) without the need of additionally moving the sample under investigation during the measurement. The system meets all requirements of ASTM 1021 and exceeds the standard requirements by performing I-V measurements for each wavelength, ¿, along with the possibility to investigate the temperature dependence of QE, IQE and short circuit current, Isc. The system is fully PC controlled, thus allowing PC controlled conditions of white light, DC biasing and temperature. The temperature can span the range 10 - 45°C. The compact design of the light delivery module provides capability for the system to obtain QE, IQE or Isc maps. The full width at half maximum for the beam was determined to be 495 microns. The system can provide 1 nm spectral resolution. The analysis of IQE versus wavelength (¿) curves we obtained (uncertainty in measurement ± 0.7 %) demonstrates that the system presented in this paper is suitable for determining the key parameters for the quantification of minority carrier recombination rate in solar cells.