Magneto-optics of InAs/GaSb superlattices

We investigate the optical and electrical properties of a series of InAs/GaSb superlattices (SLs) as a function of InAs layer width d, from 21 to 55 angstrom, with a fixed GaSb layer width of 24 angstrom, corresponding to SLs with the cutoff wavelengths between 4 and 19 mu m. Since the higher electron mass in InAs/GaSb SLs than in mercury cadmium telluride should lead to lower photodiode tunneling currents, we also measured the cyclotron effective mass for a very long wavelength infrared design SLs. For d<40 angstrom, the SLs were p-type, with hole mobilities of approximately 8 000 cm(2)/V s. For a high mobility p-type sample no hole cyclotron resonance signal was detected. However, the SLs with d >= 40 angstrom were n-type, with electron mobilities increasing from 865 to 6126 cm(2)/V s. Cyclotron resonance data on an n-type SL sample yielded an electron cyclotron mass of 0.068 m(0), which is three times the InAs bulk value of 0.023 m(0). The mass enhancement was only partially accounted for by conduction band nonparabolicity, based on our 8 X 8 envelope function calculation. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3391976]