Noise measurements for the performance analysis of infrared photodetectors

Evaluating the performances of infrared photodetectors requires both electrical and optical measurements, including a detailed analysis of the noise behavior. Indeed, in such detectors, noise can arise from the absorbing layer (Schottky noise due to photonic and dark currents, thermal noise, low frequency noise due to technological imperfections) as well as from the read-out integrated circuit (ROIC) or from the analog to digital converter (ADC). Therefore, it is of great importance to carry out noise measurements on single elements (without ROIC and ADC) as well as on focal plane arrays. In this paper, we present noise measurements on single detectors and on a large format focal plane array, both suitable to address the 3-5 mu m spectral range. The single detectors are InAs/GaSb superlattice pin photodiodes which already proved to be a very promising emerging technology, whereas the focal plane array relies on the well established, high performance InSb technology.