Abstract
Dark noise plays an important role in electronic devices, especially in detectors. Performance of infrared detectors is reflected by parameters such as detectivity and specific detectivity, strongly related to the noise spectral density. This work summarizes the results on characterization of high-performance PbS photo detectors, using a certification pending method developed by the laboratory, in agreement to the standard ISO/CEI 17025:2005. The method is validated for a resistor of known resistance, by comparing the Johnson thermal noise using two different methods: first, the fast Fourier transform measured with a Stanford Research Systems SR785 Spectrum Analyzer and second using a Stanford SR830 lock-in amplifier which measures the rms noise for a certain frequency. We studied the influence of physical dimensions on the performance of thin film polycrystalline PbS photoresistors in the planar geometry. Measurements were performed to compare the dark noise of PbS photoresistors with that in high quality metal thin film resistors. The laboratory setup used for the measurements is appropriate to accurately determine typical parameters of infrared detectors such as spectral responsivity, blackbody responsivity, specific detectivity, and noise spectral density.