Aluminium arsenide antimonide, or AlAsSb (
AlAs1-xSbx), is a ternary
III-Vsemiconductor compound. It can be considered as an alloy between
aluminium arsenide and
aluminium antimonide. The alloy can contain any ratio between arsenic and antimony. AlAsSb refers generally to any composition of the alloy.
The room temperature (T = 300
K)
bandgap and
lattice constant of AlAsSb alloys are between those of pure
AlAs (a = 0.566 nm, Eg = 2.16 eV) and
AlSb (a = 0.614 nm, Eg = 1.62 eV).[2] Over all compositions, the bandgap is indirect, like it is in pure AlAs and AlSb. AlAsSb shares the same
zincblende crystal structure as AlAs and AlSb.
Applications
AlAsSb can be lattice-matched to
GaSb,
InAs and
InP substrates, making it useful for
heterostructures grown on these substrates.
AlAsSb is occasionally employed as a wide-bandgap barrier layer in
InAsSb-based
infrared barrier
photodetectors.[3][4] In these devices, a thin layer of AlAsSb is grown between doped, smaller-bandgap InAsSb layers. These device geometries are frequently referred to as "nbn" or "nbp" photodetectors, indicating a sequence of an
n-doped layer, followed by a barrier layer, followed by an n- or
p-doped layer. A large discontinuity is introduced into the conduction band minimum by the AlAsSb barrier layer, which restricts the flow of electrons (but not
holes) through the photodetector in a manner that reduces the photodetector's
dark current and improves its noise characteristics.[5]
^
abVurgaftman, I., Meyer, J. R., Ram-Mohan, L. R. (2001). "Band parameters for III–V compound semiconductors and their alloys". Journal of Applied Physics. 89 (11): 5815–5875.
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2001JAP....89.5815V.
doi:
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^Fastenau, J. M., Lubyshev, D., Nelson, S. A., Fetters, M., Krysiak, H., Zeng, J., Kattner, M., Frey, P., Liu, A. W. K., Morgan, A. O., Edwards, S. A., Dennis, R., Beech, K., Burrows, D., Patnaude, K., Faska, R., Bundas, J., Reisinger, A., Sundaram, M. (2019). "Direct MBE growth of metamorphic nBn infrared photodetectors on 150 mm Ge-Si substrates for heterogeneous integration". Journal of Vacuum Science & Technology B. 37 (3): 031216.
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^Soibel, A., Hill, C. J., Keo, S. A., Hoglund, L., Rosenberg, R., Kowalczyk, R., Khoshakhlagh, A., Fisher, A., Ting, D. Z.-Y., Gunapala, S. D. (2015). "Room temperature performance of mid-wavelength infrared InAsSb nBn detectors". Infrared Physics & Technology. 70: 121–124.
Bibcode:
2015InPhT..70..121S.
doi:
10.1016/j.infrared.2014.09.030.