Study of the spectral response for HgCdTe long-wavelength detectors with applied stress

In the field of infrared measurement, the Fourier transform infrared (FTIR) spectrometer has important application value based on its advantages in terms of high flux and high signal-to-noise ratio. Due to the extremely low operation temperature, which is usually approximately 80 K, stress caused by thermal mismatch is a key factor affecting the performance of HgCdTe infrared focal plane detectors. However, there are few studies on the effect of mechanical stresses on the electrical performance of HgCdTe infrared detectors. Therefore, experiments were performed to research the effects of applied stresses with different properties and magnitudes on changes in the spectrum of a HgCdTe chip. The chip was divided into three regions (Region 1, Region 2, and Region 3) according to different forces. The experimental results were analyzed by finite element analysis and stress band theory. Finally, the results showed that when compressive stress was applied, the cutoff wavelength of the HgCdTe chip in Region 1 was shifted to the left, and the cutoff wavelength was restored when the degree of compressive stress increased. When tensile stress was applied, the opposite result was observed, and the cutoff wavelength did not recover when the tensile stress increased. Regardless of whether compressive stress or tensile stress was applied, there was no significant change in Region 2, while the trend in Region 3 was similar to that in Region 1.