SHIFTS AND SPLITTING OF ENERGY-BANDS IN ELASTICALLY STRAINED INGAP GAAS(111)B EPITAXIAL-FILMS/

Strain-induced shifts and splitting of energy bands are studied by opt ical techniques in compressively strained pseudomorphic InxGa1-xP film s grown by liquid phase epitaxy on lattice-mismatched GaAs(111)B subst rates. The elastic strains are measured by the x-ray diffraction techn ique and reach the value of 0.92%. The splitting of the valence band i s revealed as a doubler in the derivative of a photocurrent spectrum w hich is precisely measured on the semiconductor-electrolyte interface near the fundamental absorption edge. The maximum splitting reaches 45 meV. The sublinear behavior of the valence band splitting versus elas tic strain is clearly observed. This nonlinearity is explained by the interaction between the strain-split subband with J = 3/2, m(J) = +/- 1/2 and the spin-orbit, split subband (J=1/2, m(J) = +/- 1/2). The exp erimentally 3/2, m,= measured dependences of shifts and splitting on t he magnitude of strain are well described by the theoretical calculati ons. (C) 1997 American Institute of Physics.