While integrating spheres are known to decrease sensitivity, the use of the InGaAs detector with the integrating sphere enables high S/N and resolution.įigure 4. a long-wavelength cut-off around 1.1 m6µ for silicon-based devices. We can see that the operating temperature of bulk intrinsic IR detectors (HgCdTe and PbSnTe) is higher. Figure 4 shows the measurements at varying incident angles with a spectral a bandwidth of 1 nm. FOV are shown as a function of cutoff wavelength. The absolute reflectance measurement system with an integrating sphere was used to measure a 1050 nm laser cut-off filter. Variable angle measurement using Integrating sphere Transmission spectra of 1.3 µm band frequency cut filter The data indicate that even at the maximum scan speed of 400 nm/min, good S/N and spectral shape are well maintained.įigure 3.
As can be seen, the cutoff wavelength is shifted to lower values with increasing Cd.
Transmission spectra of 1050 nm laser cut filterįigure 3 shows the results of a 1.3 µm band frequency cut-off filter at varying scan speeds. PbS with some percentages of Cd (CdxPb1xS) were prepared, and. Low Cost MWIR InAsSb Detection Modules and Arrays Mercury (Hg), Cadmium (Cd) and Lead (Pb) Free PbS, PbSe Infrared Detectors. Both characteristics are not observed at larger bandwidths and at the smallest bandwidth – 0.2 nm, good S/N is still maintained.įigure 2. Small bandwidths enable high-resolution visualization of the edge of the cut-off filter, as well as the interference curve of a multi-layer filter. Transmission spectra of 1.3 µm band frequency cut filterįigure 2 shows the results of a 1050 nm laser cut filter at varying spectral bandwidths. with bulk bandgap energy of 2.41 eV 2,3, corresponding to an optical cut-off of 515 nm, with exciton Bohr radius (r B ) of 3 nm. As seen in Figure 1, the spectra obtained with the InGaAs detector shows a much higher S/N than those with a PbS detector.įigure 1. The spectra were obtained using two different UV-visible/NIR spectrophotometers one using a PbS detector and the other using an InGaAs detector. We attribute this improvement to the more effective oxidation process due to a large increase in the density of the grain boundaries as a result of a smaller grain size.Figure 1 shows the results for a 1.3 µm band frequency cut-off filter used for optical communications. Importantly, reduction of the growth temperature leads to a better photoresponse (up to two orders of magnitude) following the O 2 sensitization of the PbSe 0.6S 0.4 films. As shown in Figure 3, Qdots can be excited by light over a broad range of wavelengths, particularly in the UV range. The excitation wavelength was varied from 250 nm to 610 nm in 1 nm increments. The high temperature growth at 200☌ results in films with the near-columnar fiber-like microstructure low temperature growth at 50☌ results in films with the fine equiaxed grains. The peak wavelength was then used to monitor fluorescence generated from an excitation wavelength scan. Specifically, the influences of deposition temperature on the microstructure of PbSe 0.6S 0.4 and its subsequent detectivity is evaluated. /rebates/2farticle2f10.10072fs1116-1&.com252farticle252f10. In this paper, we present the growth of PbSe 0.6S 0.4 layers by physical vapor deposition and evaluate their properties and performance as a function of the deposition temperatures (50☌ and 200☌). Lead salt detectors consisting of PbSe-PbS alloys offer detection capability in the 3-5 µm midinfrared wavelength range and exhibit responsivity at near-room temperature conditions.