Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5398446 | Journal of Luminescence | 2016 | 6 Pages |
Abstract
The temperature-dependent and excitation-dependent photoluminescence (PL) spectroscopy characterization of mid-wavelength infrared InAs/InAs1âxSbx type-II superlattices reveals evidence of carrier localization. Carrier localization is apparent in the 8Â meV PL peak position blue shift from 4Â K to 60Â K while the peak full-width-at-half-maximum is non-monotonic, peaking at 25Â K before increasing above 60Â K. In addition, competition between two recombination processes is evident in the temperature-dependent behavior of the PL peak integrated intensity under low excitation conditions: the intensity decreases from 4Â K to 80Â K, increases from 80Â K to 160Â K, and decreases above 160Â K. Excitation-dependent PL studies reveal the dominant recombination mechanism changes from free-to-bound or donor-acceptor-like recombination to excitonic or band-to-band recombination at ~60Â K. These findings suggest that carrier localization is occurring below 60Â K, and the confined carriers are holes as these are unintentionally doped n-type superlattices. The localization potentials are due to variations in the InAs1âxSbx composition, the interfaces, and the InAs and InAs1âxSbx layer widths. The width of a Gaussian distribution used to describe the density of states of the band tails due to carrier localization potentials ranges from 2Â meV-4Â meV. The larger energy corresponds to the smaller period superlattices, indicating the interface compositional variation is more prominent and creates larger localization potentials than in the longer period superlattices.
Related Topics
Physical Sciences and Engineering
Chemistry
Physical and Theoretical Chemistry
Authors
E.H. Steenbergen, J.A. Massengale, G. Ariyawansa, Y.-H. Zhang,