SHEAR DEFORMATION POTENTIAL OF ELASTICALLY STRAINED INGAP GAAS(111)B AND INGAASP/GAAS(111)B FILMS/

Elastically compressed InGaAsP epilayers were grown in a wide interval of compositions (with bandgaps from 1.4 to 1.9 eV) on GaAs(111)B subs trates by liquid phase epitaxy. The splitting of the valence band was found by taking the derivative of photocurrent spectra. Its value was as high as approximate to 60 meV for narrow-bandgap epilayers (E(g) si milar or equal to 1.45-1.55 eV) and approximate to 40-45 eV for wide-b andgap epilayers (E(g) similar or equal to 1.8-1.85 eV). The calculate d shear deformation potential, d, was found to be -4.2 +/- 0.4 eV for narrow-bandgap and -4.0 +/- 0.2 eV for wide-bandgap films. A nonlinear dependence of the valence-band splitting on elastic strain was clearl y observed for the wide-bandgap epilayers. This nonlinearity was expla ined by taking into account the interaction of the light-hole band wit h the spin-orbit-split valence band.