PHOTOREFLECTANCE AND ELECTROREFLECTANCE IN SILICON

The photoreflectance spectrum of the 3.4 eV peak of a [110] silicon surface shows a dependence on the polarization of the probing light analogous to that found for the electroreflectance spectrum. Photoreflectance measurements in the presence of externally applied surface dc electric fields show a marked increase in the intensity of the peaks when the external field is in a direction such that it increases the band bending at the semiconductor surface. The reciprocal effect, cancellation of the electroreflectance spectrum by means of a secondary light beam, has also been observed. We conclude that the photoreflectance is the electroreflectance produced by the quenching of the surface fields by photoexcited electron-hole pairs. © 1969.