26 May 2016 Infrared optical and electronic properties in low tellurium doped GaSb substrates for SLS FPA applications
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Epi-ready GaSb wafers with low absorption coefficients are of a special interest as substrates for molecular beam epitaxy (MBE) growth of material for IR focal plane arrays that operate under back-side illumination configuration, when the substrate is not completely removed. While low absorption coefficient across a broad IR spectral range (~2um-20um) is achievable in GaSb crystals with low Te doping, the control of the doping distribution across the wafers is especially challenging in the mass-production of optically transparent, high-resistivity Te-doped GaSb wafers. In this work, we examine data from the n-type and p-type Te-doped GaSb samples with doping concentration below 1e18 cm-3. The carrier concentration measured by the Hall and the transmission data measured by FTIR spectroscopy are correlated. We perform a rigorous analysis of the absorption coefficient based on the free-carrier absorption mechanism that is dominant for the n-type GaSb and the inter-valence band absorption due to the transitions from the light-hole to the heavy-hole band that is the dominant absorption mechanism for the p-type GaSb. Based on the correlation between the Hall and the FTIR data, carrier concentration profile can be estimated from the non-destructive FTIR transmission mapping of the wafer.
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K. Roodenko, K. Roodenko, P.-K. Liao, P.-K. Liao, D. Lan, D. Lan, K. P. Clark, K. P. Clark, E. D. Fraser, E. D. Fraser, K. W. Vargason, K. W. Vargason, J.-M. Kuo, J.-M. Kuo, Y.-C. Kao, Y.-C. Kao, P. R. Pinsukanjana, P. R. Pinsukanjana, } "Infrared optical and electronic properties in low tellurium doped GaSb substrates for SLS FPA applications ", Proc. SPIE 9854, Image Sensing Technologies: Materials, Devices, Systems, and Applications III, 985415 (26 May 2016); doi: 10.1117/12.2234694; https://doi.org/10.1117/12.2234694


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