Journal of Vacuum Science & Technology B, Vol.23, No.3, 1149-1153, 2005
Optical properties of (GaSb)(3n)(AlSb)(n) (1 <= n <= 5) superlattices
We report room-temperature pseudodielectric function spectra = + i from 1.5 to 6.0 eV of a series of (GaSb)(3n)(AlSb)(n) (1 <= n <= 5) short-period superlattices (SLs) and the corresponding ternary alloy, Al0.3Ga0.7Sb, as determined by spectroscopic ellipsometry. An in situ chemical etching procedure was performed to minimize the effect of surface oxides and other overlayers. For small periods (n <= 2), the dielectric responses of the SLs are similar to those of the random alloy. For larger it, structures due to the E-1, E-1 + Delta(1), E-0', E-2, and E-1' interband transitions can be seen, with the E-1, E-1+Delta(1), and E-0' structures showing a clear SL-period dependence. Two additional features were also observed near the E-1+Delta(1) structure for n >= 4. (c) 2005 American Vacuum Society.