E. Reguzzoni

Infra-red properties of bulk heavily doped silicon

SummaryIn this work reflectance (R) and thermoreflectance (TR) spectra in the infra-red of bulk P and B heavily doped silicon samples are reported and discussed. The values of the scattering time and of the effective mass, as well as the temperature derivative of the plasma frequency, scattering time and high-frequency dielectric constant are extracted from the data and analysed in terms of free-carrier-photon and free-carrier-impurity interaction.RiassuntoIn questo lavoro sono riportati e discussi gli spettri di riflettanza (R) e termoriflettanza (TR) in infrarosso di campioni di silicio drogati pesantemente per diffusione con P e B. Dai dati sono ricavati i valori dei tempi di rilassamento e della massa effettiva, come pure la derivata in temperatura della frequenza di plasma, del tempo di rilassamento e della costante dielettrica ad alta frequenza, che sono analizzati sulla base delle interazioni fra portatori liberi e fononi e fra portatori liberi e impurezze.

Thermo-optical response of VxTi1-xSe2 in the plasmon reion

Abstract It is shown that some structure growing on the high energy side of the plasmon when cooling TiSe 2 crystals through the transition temperature is smeared out with vanadium concentrations of the order of 1% and that the plasmon lifetime is considerably affected both by temperature and vanadium content.

Thermoreflectance lineshape modifications induced by the magnetic ordering

Abstract Recently strong modifications in the intensity and the shape of thermoreflectance (TR) spectra in ferromagnetic crystals near the transition temperature have been reported. In this letter we propose a phenomenological model, based on the band splitting by the molecular field, which rather well explains the changes observed in the TR spectrum of CrBr3 near 7eV.

Effect of heavy doping on the optical spectra of silicon

In this paper reflectance (R) and thermoreflectance (TR) spectra in heavily doped silicon concerning both interband and intraband transitions are reported and discussed. The heavily doped sample shows a red-shift and lifetime broadening in the two singularities E1(similar 3.4eV) and E2(similar 4.5eV). The values of the scattering time τ extracted from the reflectivity fit are obtained and compared with those obtained from Hall mobility measurements.

Microprocessor‐controlled magneto‐optics apparatus

We describe a new apparatus which measures the reflectance and magneto‐thermoreflectance at normal incidence in Faraday geometry, with an external magnetic field up to 2.3 T and with circularly polarized light in the spectral range 220–2000 nm. The sample temperature may be changed from 5 to 300 K continuously. The experimental variables (wavelength, polarization, temperature, and magnetic field) are controlled by a low‐cost microcomputer which also performs the data acquisition and preprocessing, in which the data fluctuations are reduced with multiscaler and smoothing techniques.

Some aspects of vacuum ultraviolet thermoreflectance spectra

Abstract Vacuum ultraviolet thermoreflectance spectra of Ge, GaAs, InSb and CdTe are analyzed. A direct comparison of the measured and calculated reflectivity peaks is made. The Rydberg series of the Γ 1 exciton is observed in the thermoreflectance spectrum of RbI and KI. The energy gap, the exciton binding energy, and the electron effective masses are then determined.