13 May 2015 Studies on abrupt and gradual band gap hole barriers in InAs/GaSb superlattice long wavelength photodetectors
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The barrier enhanced InAs/GaSb long wavelength photodetectors were proved to have better performance. Our previous work showed a PBIN detector with an electron barrier inserted show significantly improved electrical performances compared to a PIN structure. To improve the quantum efficiency, Be-doping was employed to convert the conductivity of the long wavelength SL structure, the PN junction moves away from the B-I hetrostructure to the π-N interface which loses the barrier effect. Therefore, the hole barrier was needed to form a PBπBN structure. In this paper, both the abrupt and gradual hole barrier was designed without Al element to form a PBπBN structure. The gradual hole barrier was optimized to avoid the blocking of photo generated current, maximized the quantum efficiency. The RmaxA product of the PBπBN detector was measured to be 77 Ωcm2 and the dark current density under -0.05V bias was measured to be 8.8×10-4A/cm2 at 80K. The quantum efficiency of gradual hole barrier detector was measured to be 27.2% at 10.6 μm and the quantum efficiency was slowly decreased under reverse bias. The result shows the gradual hole barrier efficiently eliminate the peak barrier in the electron band. The peak detectivity of this graded detector is calculated to be 9.46×1010cm.Hz1/2.W-1 at 10.6 μm.
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Yi Zhou, Yi Zhou, Jianxin Chen, Jianxin Chen, Fangfang Wang, Fangfang Wang, Zhicheng Xu, Zhicheng Xu, Zhizhong Bai, Zhizhong Bai, Chuan Jin, Chuan Jin, Li He, Li He, } "Studies on abrupt and gradual band gap hole barriers in InAs/GaSb superlattice long wavelength photodetectors", Proc. SPIE 9481, Image Sensing Technologies: Materials, Devices, Systems, and Applications II, 94810V (13 May 2015); doi: 10.1117/12.2179742; https://doi.org/10.1117/12.2179742

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