Excited states of Ag and Cu acceptors in CdTe

We report on resonantly excited luminescence (REL) at 1.8 K and infrared absorption (IRA) between 6–12 K of CdTe doped with Ag and Cu impurities. The luminescence was excited with a tunable dye laser. Two hole transitions up to $\text{6}\text{S}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$ state have been observed, the bound exciton lines have been identified. $\text{2}\text{P}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}$ states have been observed in IRA measurements. The binding energies as deduced from REL experiments are 107.5 meV for Ag and 146 meV for Cu. The fitted values of the valence band parameters are Ro = 27 ± 3 meV μ = 0.73 ± 0.03 and δ = 0.12 ± 0.01.     

Identification of Cu and Ag acceptors in CdTe

We report here on the identification of the two dominant acceptor levels in high purity p type CdTe, with Cu and Ag on Cd site. This identification is based on back doping experiments coupled with electrical measurements and photoluminescence studies. Cu and Ag can form easily complex centers when a supersaturation is achieved. The way of obtained good doping without complexation, is explained. The principal bound exciton lines are at 1,5896 eV (Cu) and at 1,5885 eV (Ag). The precise hole binding energies obtained from optical data are E_A (Cu) = 146 meV and E_A (Ag) = 108 meV.     

Study of structural and electronic transport properties of Ce-doped LaMnO3

The structural and electronic transport properties of La_1−x Ce _x MnO₃ (x=0.0–1.0) have been studied. All the samples exhibit orthorhombic crystal symmetry and the unit cell volume decreases with Ce doping. They also make a metal-insulator transition (MIT) and transition temperature increases with increase in Ce concentration up to 50% doping. The system La_0.5Ce_0.5MnO₃ also exhibits MIT instead of charge-ordered state as observed in the hole doped systems of the same composition.     

Infrared focal plane array with a built-in stationary Fourier-transform spectrometer: basic concepts

A novel configuration of stationary Fourier transform infrared (FTIR) spectrometer is presented. Contrary to classic configurations, the interferometer is directly integrated in the focal plane array (FPA) during its process of fabrication. A first, to the best of our knowledge, demonstration of the spectrometric function has been achieved departing from a well-known structure of an HgCdTe photodetector. We show that the obtained FTIR-FPA can be described by intrinsic parameters such as an optical path difference and a so-called spectrometric efficiency. First experimental results are presented.     

Two connected inverse spectral transforms

We establish a transformation which connects the potentials of the one-dimensional Dirac and Klein-Gordon operators. This transformation links the solutions of the nonlinear evolution equations solvable by means of the two inverse spectral transforms which use the Dirac and Klein-Gordon direct and inverse spectral problems.