Implementation and uncertainty evaluation of spectral stray light correction by Zong's method.

We present a guide to the implementation and uncertainty evaluation for spectral stray light corrections according to the widely used method as proposed by Zong et al. [Appl. Opt.45, 1111 (2006)APOPAI0003-693510.1364/AO.45.001111]. The uncertainty analysis is based on the Monte Carlo approach in accordance with the Guide to the Expression of Uncertainty in Measurement (JCGM, Paris, 2008). We show that significant uncertainty contributions result from drifts of the spectrometer's dark signal and the width of the in-band region selected for shaping stray light distribution functions. Additionally, a simplified method for estimating these uncertainty contributions is presented, which does not require a complex Monte Carlo analysis. We also show that stray light correction may introduce correlations with respect to wavelength.

Instrumentation-related uncertainty of reflectance and transmittance measurements with a two-channel spectrophotometer.

Spectrophotometers are operated in numerous fields of science and industry for a variety of applications. In order to provide confidence for the measured data, analyzing the associated uncertainty is valuable. However, the uncertainty of the measurement results is often unknown or reduced to sample-related contributions. In this paper, we describe our approach for the systematic determination of the measurement uncertainty of the commercially available two-channel spectrophotometer Agilent Cary 5000 in accordance with the Guide to the expression of uncertainty in measurements. We focus on the instrumentation-related uncertainty contributions rather than the specific application and thus outline a general procedure which can be adapted for other instruments. Moreover, we discover a systematic signal deviation due to the inertia of the measurement amplifier and develop and apply a correction procedure. Thereby we increase the usable dynamic range of the instrument by more than one order of magnitude. We present methods for the quantification of the uncertainty contributions and combine them into an uncertainty budget for the device.

Experimental setup for camera-based measurements of electrically and optically stimulated luminescence of silicon solar cells and wafers.

We report in detail on the luminescence imaging setup developed within the last years in our laboratory. In this setup, the luminescence emission of silicon solar cells or silicon wafers is analyzed quantitatively. Charge carriers are excited electrically (electroluminescence) using a power supply for carrier injection or optically (photoluminescence) using a laser as illumination source. The luminescence emission arising from the radiative recombination of the stimulated charge carriers is measured spatially resolved using a camera. We give details of the various components including cameras, optical filters for electro- and photo-luminescence, the semiconductor laser and the four-quadrant power supply. We compare a silicon charged-coupled device (CCD) camera with a back-illuminated silicon CCD camera comprising an electron multiplier gain and a complementary metal oxide semiconductor indium gallium arsenide camera. For the detection of the luminescence emission of silicon we analyze the dominant noise sources along with the signal-to-noise ratio of all three cameras at different operation conditions.