Measurement of the optical constants of crystal quartz at 10 K and 300 K in the far infrared spectral range: 10–600 cm−1

The optical constants of crystal quartz in the far infrared (10 – 600 cm^?1) are reported at room temperature and at 10 K, for both polarizations parallel and perpendicular to the c-axis, respectively extraordinary and ordinary ray. These constants are obtained from the analysis of the transmissivity channeled spectra below 300 cm^?1, and from the analysis of the reflectivity spectra between 300 – 600 cm^?1, measured by using a grating infrared spectrometer. The extrapolated zero frequency refractive indices of quartz obtained in the present work are: n_o(0) = 2.106 and n_e(0) = 2.153 at 300 K; n_o(0) = 2.072 and n_e(0) = 2.130 at 10 K.     

A two-beam interferometer for dispersive reflection spectroscopy of solids in the far infrared at temperatures between 4 and 300K

A Fourier spectrometer has been developed for determining the optical constants of highly absorbing solids in the far infrared at temperatures down to 4.2K from measurements of their amplitude and phase reflection spectra. The spectrometer has been constructed almost entirely from commercially available components, and its performance is illustrated with measurements of the optical constants of NaCl at 6K.     

Optical properties of intrinsic silicon at 300 K

An updated tabulation is presented of the optical properties of intrinsic silicon relevant to solar cell calculations. the absorption coeficient, refractive index and extinction coeficient at 300 K are tabulated over the 0.25-1.45 μm wavelength range at 0.01 μm intervals.     

Threshold field and peak-valley velocity ratio in short samples of InP at 300 K

The transient and steady-state velocity-field characteristics of InP at 300 K are calculated for short samples by using a Monte Carlo model. It is found that the threshold field for negative differential resistance increases with a decrease in the sample length, but the peak-valley velocity ratio is almost independent of the sample length.     

Frequency limits of GaAs and InP field-effect transistors at 300 K and 77 K with typical active-layer doping

InP FET's with active layer doping of 10¹⁷donors/ cm³have limiting values of fTroughly fifty per cent higher than those of equivalent GaAs devices for lengths ranging from 0.5 µm to 3 µm at 300 K, and from eighty percent to forty percent higher in this gate length range at 77 K.     

Study of the far infrared optical properties of KI by dispersive Fourier transform spectrometry

The optical constants of KI have been determined in the far infrared at 200 and 300K by dispersive Fourier transform spectrometry and used to calculate the imaginary part of the anharmonic self-energy of the q?o transverse optic mode. The overall agreement, both quãlitatively and quantitatively, with calculations by Berg and Bell and by E?dridge and Kembry which include contributions from cubic anharmonicity is good.     

远红外光学薄膜的热特性研究

本文采用表面热透镜技术对10.6μmCO2激光辐照下的样品微弱吸收进行了研究,并对实验结果进行了分析。对10.6μm激光辐照下光学薄膜样品中的温度场进行了数值模拟,应用夏克—哈特曼波前传感器对几种不同的基底材料和光学薄膜在10.6μm激光辐照下的热畸变进行了测量。     

远红外Ge-Te-Ag硫系玻璃的光学性能研究

用熔融淬冷法制备了一系列Ge-Te-Ag硫系玻璃,并确定了玻璃态的成玻区。通过阿基米德排水法、X射线衍射(XRD)、差示扫描量热(DSC)、可见/近红外吸收(UV-VIS-NIR)光谱和傅里叶红外透射(FTIR)光谱等技术,研究了玻璃态的物理特性、热学特性以及光学特性。研究表明,玻璃态的密度随着Ag含量的增加而增大;Ag的掺入改善了玻璃态的形成能力和热稳定性;随着Ag含量的增加,玻璃态的短波吸收限发生了红移,而红外截止波长基本没变化;玻璃态有着较宽的红外透过范围(1.8～20.0μm),表明其在远红外领域具有很大的应用前景。     

Surface resistance and far infrared absorptivity at T=7 K of highT c YBaCuO superconductors

A surface resistance as small as R_S=3×10^?2 Ohms has been computed at T=8 K, for v=0.6 Thz (v=20 cm^?1), for an YBaCuO film deposited on an MgO substrate. The calculations are made with the refractive index computed from the Far IR transmission spectra of a 400 Å thick film. Still lower values are obtained with another sample, 300 Å thick of exceptional quality (R_S=1.2×10^?2 Ohms).     

Modes of a tilted-mirror optical resonator for the far infrared

In an extension of the work of A. G. Fox and T. Li of Bell Telephone Laboratories, a study was made of the modes of tilted-plane mirrors having enough tilt to use the spillover radiation (at a straight edge) as output coupling. This geometry seems desirable as an oscillator to intercept a molecular beam and extract coherent power in the far infrared. Control of the tilt angle provides variableQ. Amplitude and phase of the output are smooth enough to use cylindrical optics for focusing or collimating the output. The three lowest-order two-dimensional modes were studied which, under reasonable conditions, are determined by a single parameter. It isbeta = alpha(b/lambda)^{1/2}, where α = mirror tilt, b = mirror separation, and λ = wavelength. The lowest mode (TEM0) has loss per pass that increases almost linearly from 3 percent atbeta = 10^{-2}to 37 percent atbeta = 10^{-1}. The output appears to diverge from a virtual source about 3b behind the spillover edge of the shorter mirror. The virtual source of the lowest mode is displaced (0.7 to 1.1)(lambda b)^{1/2}inward from the spillover edge. The mathematical problem proved to be an interesting exercise in devising ways to isolate an eigenfunction of an integral operator when the eigenvalues are nearly equal.     

High-gain cerenkov free-electron laser at far infrared wavelengths

The small-signal gain is derived for a Cerenkov free-electron laser operating in the collective beam limit. The device consists of two dielectrically lined parallel plates driven by a cold, relativistic electron beam. The dependence of the output wavelength on the resonator parameters and the electron beam energy is examined with particular attention devoted to device operation in the far infrared and submillimeter portion of the electromagnetic spectrum at moderate electron beam energies (gamma < 3).     

Spectroscopic studies of optical materials in the far infrared: The case of crystal quartz

Spectroscopic studies using far infrared reflectivity and transmissivity measurements between 10 and 600 cm^?1, were performed on plane parallel quartz crystal plates, in the temperature range 10–300 K. The temperature dependence of the optical mode parameters is reporeted for both polarizations parallel and perpendicular to the c-axis. The extraordinary optical constants of quartz are determined at 10 and 300 K, from the A₂ transmissivity channeled spectrum, between 10 and 300 cm^?1.     

Aluminum multiple implantations in 6H–SiC at 300 K

A complete study was driven in order to elaborate a p⁺–n junction in 6H–SiC. The chosen techniques were aluminum multiple implantations, followed with high-temperature furnace annealings. First, we had to configure the furnace geometry aiming at optimizing the annealed material characteristics. We evidenced the beneficial effects of a SiC plate inside the furnace reactor on the surface stoichiometry of the annealed sample, and also on its crystal reordering velocity. Then, the fivefold aluminum implantation necessary for the 0.5 μm depth p⁺-region creation has been studied, especially the energy order influence on the junction steepness. It was found that the increasing energy order implantations lead to a channeling effect less important, a deeper amorphized zone, and a defect interface at volume more abrupt. After an annealing performed with the optimized furnace, the best electrical activation obtained equated the degree of ionization even though the as-implanted material was totally amorphized up to 0.25 μm. Moreover, the three different multiple implantations investigated during this study induced different amorphized layer depths, despite they all have the same total aluminum dose with the same highest energy value. All along the paper, we propose to explain this fact. This is probably due to distinct mechanisms involved in the amorphization phenomena, which were tentatively estimated with a specific Monte Carlo simulator recently developed.     

The effect of hydrostatic pressure on the electronic and optical properties of InP

Based on the empirical pseudo-potential method, the electronic and optical properties of the InP compound in the zinc-blende structure at ambient and under hydrostatic pressure are reported. The first-order pressure coefficients of the main band gaps (at Γ, X, and L) are given. The agreement between our calculated hydrostatic deformation potential and the available experimental data is better than 5%, whereas for the crossover pressure from direct to indirect band gap is about 10% less. The valence bandwidth increases with increasing pressure reflecting the decreased ionicity in the material of interest. Besides the electronic properties, the effect of pressure on the dielectric function is also analysed.     

The far infrared complex reflectivity of GaTe

The room temperature polarized complex (amplitude and phase) infra-red reflection spectra of single crystal monoclinic GaTe have been measured between 20 and 400 cm^?1 using a dispersive Fourier transform spectrometer. The measurements allow the experimental zone centre transverse and longitudinal phonon modes and optical constants to be determined without recourse to oscillator fit models or Kramers-Kronig analysis. Infrared power transmission measurements have allowed all fifteen predicted modes to be identified and the results are compared to recent Raman work.     

Cross-sectional TEM of Pd/InP and Au/lnP interfaces formed at substrate temperatures near 300 and 77K

Depositing Pd or Au on InP at cryogenic substrate temperatures has previously been found to significantly increase the barrier height of the resulting Schottky diode. In this work, cross-sectional transmission electron microscopy was used to determine the structural differences between metal/semiconductor (MS) interfaces formed at 300K (RT) and at 77K (LT). In the Pd/lnP case, RT samples exhibited a thick amorphous interaction layer at the MS interface, while LT samples only had a thin phosphorous-rich interfacial layer. However, in the Au/InP case, no amorphous interlayers were observed in any of the samples. Instead, a small amount of Au was found to extend into the InP lattice in the RT case which was not present in LT samples. The thermal stability of the barrier height was studied as well. LT Au/lnP samples were found to exhibit a distinct barrier height shift when annealed at 200°C which was linked to a grain coarsening in the polycrystalline Au layer at this temperature. X-ray diffraction was used to verify changes in the polycrystalline metal's average grain size. We conclude that a significant reduction in the interaction between the deposited metal and InP was responsible for the greatly enhanced barrier height observed in LT interfaces.     

Resistivity and mobility of GaP at 300 K

Resistivity and mobility data of GaP at 300 K are presented in a unified form as a function of impurity concentration for the first time. The data are determined from sheet Hall coefficient and resistivity measurements obtained using the van der Pauw method. The results are given over a wide range of concentrations ranging from unitentionally doped to degenerate conditions. The maximum values of the electron and hole mobility, µnand µp, are found to be 160 and 135 cm²/V . s, respectively.     

硫系玻璃红外光纤的特性和应用研究

本文综述了硫系玻璃红外光纤的材料特性和应用研究,并展望了该材料的发展前景。     

The electrical and optical properties of InP irradiated with high integrated fluxes of neutrons

The results of studying the electrical properties and optical-absorption spectra of InP irradiated with fast neutrons (E > 0.1 MeV and D_f.n ≤ 10¹⁹ cm^?2) and full-spectrum reactor neutrons (D_th.n ≤ 2.1 × 10¹⁹ cm^?2; the ratio of the fluxes was ?_th.n/?_f.n ≈ 1) are reported. The variations in these properties resulting from postirradiation annealing at temperatures as high as 900°C are also studied. The results of the optical studies indicate that, in InP irradiated heavily with neutrons, free charge carriers appear only after annealing at temperatures higher than 500°C. The efficiency of neutron-initiated transmutational doping and the quality of transmutationdoped InP are assessed.     

1C6--Cyclotron resonance in semiconductors with far infrared laser

The quantum effects in the degenerate valence bands of germanium have been observed as multiple cyclotron resonance absorption lines at a temperature of 165°K. Additional lines were resolved at 40°K. The combination of high intensity magnetic fields up to 180 000 gauss and the output power of a cyanide submillimeter laser (0.337 millimeters) was used. The construction and operation of a simple resonance spectrometer is described. Cryogenic techniques and the choice of detectors are discussed. The possible use of molecular gas laser spectrometers for EPR, ferrimagnetic resonance, and antiferromagnetic resonance at submillimeter wavelengths is considered.