M. Balkanski

Raman scattering from localized vibrational modes of boron impurities in silicon

Abstract Reflection Raman spectroscopy has been performed on boron doped uncompensated silicon wafers. The doping of 1.5 10 20 cm −3 is obtained by diffusion. Two localized modes associated with B 10 and B 11 are observed respectively at 642 and 619 cm −1 . The position of the peaks does not differ more than 2 cm − from the infrared absorption results, obtained with compensated samples.

Line-shapes of localized impurity phonon modes of boron acceptors in silicon

Abstract The Raman scattering cross-section of localized phonon modes due to impurities has been measured. Interference effects between the localized phonon and electronic continuum scattering amplitudes are signalled by the onset line-shape asymmetries. Qualitative analysis of the results is given in terms of the Fano theory.

Resonant Raman scattering near the 1S exciton level in cuprous oxide

Abstract Raman scattering experiments on the Γ 15 − LO 1 mode in Cu 2 O crystals were performed using incident light near the resonance with the 1 S exciton level of the ‘yellow serie’. The enhancement of the Raman efficiency observed in this experiment is attributed to the activation of the normally forbidden transition by stoechiometric defects in the Cu 2 O crystals.

Band crossing in Pb1−xSnxSe under hydrostatic pressure☆

Abstract Laser emission from Pb 1−x Sn x Se diodes for x = 0.115 at 78.5°K is observed under hydrostatic pressure up to 14.7kbar. Direct evidence for an inversion of valence and conduction bands is obtained from the pressure coefficient measured on the same diode over the whole experimental range. We discuss briefly the nature of the band structure after the cross over point and suggest an explanation for an abrupt increase of the threshold current for laser action in these diodes at small gaps.

Spin-flip Raman scattering in CdS and High resolution spectroscopy near 5145 Å

Abstract Spin-flip Raman scattering is observed in CdS, from electrons bound to donors, using the 5145 A line of an argon-ion laser. A high improvement is provided by the use of an iodine vapour cell in the scattered beam to filter the stray light at excitation frequency. Using the spin-flip line as a magnetically tuneable source a high resolution absorption spectrum is obtained for I 2 , near 5145 A. A technique is suggested to improve the accuracy in the determination of the g factor, and to measure low g values and g -factor anisotropies.

Detailed Structure of Electronic Surface State Densities in the Gap of Semiconductors by Photoemission Measurements

The acrlibrate measurements of the photoemission yield, down to the 10−10 range, as a function of photon energy in the threshold region, can give a precise information on the electronic surface state density in the band gap of semiconductors. The method is illustrated with results obtained on the (111) face of silicon, clean or after interaction with oxygen or hydrogen, and on the (1010) face of CdS clean, or after interaction with oxygen.