Electronic Resource
[S.l.]
:
American Institute of Physics (AIP)
Journal of Applied Physics
81 (1997), S. 6968-6974
ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
We report the observation of oscillatory features (OFs) in the photoreflectance (PR) and contactless electroreflectance (CER) spectra of CdTe films grown on Si substrate, at energies below the band gap of CdTe. The simultaneous observation of OF in the reflectance (R) spectrum having the same period as those in the PR and CER spectra (as also their dependence on film thickness) provides a direct proof for optical interference effects as being the source of these features. However, in the present case the amplitude of the OF gets damped towards shorter wavelengths while remaining nearly wavelength independent in the longer wavelength region indicating a modulation mechanism different from those reported earlier. A series of experiments and simulations performed by us seem to indicate that while in PR the principal mechanism is the pump beam induced periodic temperature changes which in turn modulates the optical path length of the CdTe film, in CER the mechanism is the electric field induced modulation of the subband gap refractive index of the film through the electro-optic effect. The damping of the OF has been explained on the basis of subband gap absorption by the CdTe film. © 1997 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.365260
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