OPTICAL 2ND-HARMONIC GENERATION IN SI1-XGEX FILM EPITAXIALLY GROWN ONSI(100)

We have observed the optical second harmonic generation (SHG) from Si1 -xGex epitaxial films for the first time. The SH intensity was measure d as a function of Ge fraction x and the azimuthal angle of rotation o f the film about the surface normal. The SH intensity has a maximum ar ound x=0.8 similar to 0.9. The SH intensity curve as a function of the azimuthal angle shows a four-fold pattern for the Ge fraction x=0.8 s imilar to 0.9. The enhancement in the SH intensity and the signal anis otropy are believed to be due to the resonance of the incident and sec ond harmonic photon energies with the E(0) and E(1) band gaps of Si1-x Gex, respectively.