MRS Proceedings

Table of Contents - Volume  667  - Symposium G – Luminescence and Luminescent Materials  

Editors : B. DiBartolo, J. McKittrick, K.C. Mishra, P.C. Schmidt, A. Srivastava


PL due to Discrete Gap Levels in Some Chalcogenide Glasses- A Configurational Coordinate Diagram Illustration

2001 MRS Spring Meeting.

N. Asha Bhata1, K.S. Sangunnia1 and K.S.R.K. Raoa1

a1 Department of Physics, Indian Institute of Science Bangalore –560 012, INDIA


Photoluminescence (PL) studies were carried out on a-Se and a few Ge20Se80−xBix and Ge20Se70−xBixTe10 bulk glassy semiconductors at 4.2 K with Ar+ laser as excitation source. While a-Se and samples with lesser at% of Bi show fine structured PL with a large Stokes shift, samples with higher at% of Bi did not show any detectable PL. The investigations show at least three radiative recombination transitions. Features extracted by deconvoluting the experimental spectra show that the discrete gap levels associated with the inherent coordination defects are involved in the PL transitions. Absence of PL in samples with higher Bi at% are explained on the basis of nonradiative transition mechanisms. Overall PL mechanism involving gap levels in chalcogenide glasses is illustrated with the help of a configurational coordinate diagram.