OPTICAL ENERGY-GAP VARIATION AND DEFORMATION POTENTIALS IN CUINTE2

Values of optical energy gap E0 as a function of pressure P up to 3 GPa at room temperature, and as a function of temperature T in the range 10-300 K at atmospheric pressure were obtained by optical-absorption measurements on samples of CuInTe2. It was shown that in this pressure range, E0 varies linearly with P, dE0/dP having a value of 2.2 x 10(-2) eV/GPa. The variation of E0 with T was fitted well by a simple Manoogian-Leclerc equation of the form E0(O) - E0(T) = UT + V-phi (coth-phi/2T - 1). Both dE0/dP and U can be related to (dE0/dT)2, the lattice dilation contribution to the variation of the energy gap with temperature, and the values obtained in the two cases showed good agreement. The V-phi term can be related to (dE0/dT)1, the energy-gap variation due to electron-phonon interaction. From the values of (dE0/dT)1 and (dE0/dT)2, values were determined for the acoustic deformation potentials of the conduction band C(e) and of the valence band C(h).