Resonance Raman-scattering study of narrow-gap Hg_1-xCd_xTe

Abstract

We have studied resonance Raman scattering in two samples of (llO)Hg,-xCd,Te (nominal compositions x = 0.2 and 0.3) in the region of the E, optical feature. The maximum enhancement for the 'clustering', 'HgTe-like' LO and 'CdTe-like' LoaTo modes occurs at the energy of the E, electronic transition of Hg, -,Cd,Te for our samples. The 'CdTe-like' LoaTo mode is thus identified as a propagating phonon. This is in marked contrast to a similar mode in InAs, ,Po which is localised at the P sites. Although the resonant behaviour of the 'clustering' mode suggests that it is an alloy mode, our experiment does not provide the basis for a conclusive assignment. The polarisation behaviour of the symmetry-forbidden 'HgTe-like' LO mode as well as the nature of its resonant enhancement indicate that the mechanism of the forbidden LO scattering is either the intraband Frolich interaction or impurity-induced scattering, not morphic effects as proposed in prior works.

Raman spectroscopic study of HgCdTe epilayers for infrared detector array fabrication

“…Raman spectroscopic technique has another advantage of being contactless and nondestructive method. HgTe and CdTe like transverse optical (TO) and longitudinal optical (LO) phonon features were reported using polarization dependent Raman scattering on Hg 0.8 Cd 0.2 Te and Raman scattering is reported to be sensitive to the surface condition [7][8][9][10][11][12][13]. But correlation of the phonon features with the surface condition is not attempted.…”