Quantized IR properties reconfirmed in the CO and SiO surface oscillators present in the surface layer of A bamboo stem

From analysis of diffusion diagrams of CO stretching band (2500～2180 cm^?1), bending band (800～200 cm^?1) and SiO stretching band (1100～700 cm^?1) measured in a skin surface layer of a bamboo stem (silicate cellulose), azimuthal directions where oscillators oriented were shown as (?'=?-90) ?_N=a·N-b, with a=28.3, 2×28, 22.7, b=25, 47.5, 10. And N=1,2.....14, N=1, .....6. N=1,2.....16. The optical activity (reflection integral) was shown for the CO stret. band as M_i(N)=a·N+b, with a=21.8, b=42 and N =1,2.....9. And for the bending band as M_i(N)=a·N² +b·N?c, with a=1.87×10¹, b=3.73×10³, c=7.06×10² with N=1,2.....9. Six stepnized fine series in CO weak reflection bands were confirmed as, \(\bar v = A \cdot N^2 + B \cdot N + C (cm^{ - 1} )\) and \(\bar v_{C - 1} = A \cdot N^{1/2} + B (cm^{ - 1} )\) with N=1,2.....22. Mean values of the vibrational quantized states of the A, B and C-series in the SiO stretching weak band with R?1.0% were shown as, \(\overline {\Delta E} _m = 4.54 \times \bar v_{\text{m}}^{\text{2}} - 1.449 \times \bar v_m + 1.27 \times 10^7 \) (meV) with \(\bar v = E/hc\) .     

Infrared properties of quartz fibres

The IR properties of micron-size amorphous SiO₂ fibres have been investigated between 400 cm^?1 and 1400 cm^?. For the single scattering size and shape effects have been measured and compared with theory. The observed diffuse reflection of quartz wool can be explained qualitatively by the Kubelka-Munk theory for multiple scattering.     

Ohmic contacts to InP-based materials induced by means of rapid thermal low pressure (metallorganic) chemical vapor deposition technique

A rapid-thermal-low-pressure-metallorganic-chemical-vapor-deposition (RT-LPMOCVD) technique was executed in order to deposit non-semiconductor thin layer materials, necessary for producing metal contact to InP-based microelectronic devices. Silicon dioxide (SiO₂) films were deposited onto InP substrates in rapid thermal cycles, using O₂ and 2% diluted SiH₄ in Ar, with very fast growth kinetics and low activation energy. The SiO₂ film exhibited excellent properties, such as refractivity index, density, internal stress, and wetp-etch rates. The SiO₂ films were dry etched in a given pattern to allow for the formation of a small metal contact to the InP-based material, onto which the SiO₂ layer was deposited. Subsequently, titanium-nitride (TiN _x ) thin films were deposited onto the InP substrate through rapid thermal deposition cycles, using a tetrakis (dimethylamido) titanium (DMATi) metallorganic liquid source as the precursor for the process, with fast kinetics. The deposited TiN _x films had a stoichiometric structure and contained nitrogen and titanium in a ratio close to unity, but incorporated a large amount of carbon and oxygen. The film properties, such as resistivity (40–80 μΩ·mm) and stress (compressive; ?0.5 to ?2.0×10⁹ dyne·cm^?2), were studied in addition to an intensive investigation of its microstructure and morphology, and their performance as an ohmic contacts while deposited ontop?In_0.53Ga_0.47As material (Zn doped 1.2×10¹⁸ cm^?3).     

TE On o -to- mode transducer designmode transducer design

This paper gives a structure on the mode converter from TE _0n ^O mode of gyrotron output to the main mode of the circular groove guide. The design consists of two parts: the first part is to convert TE _0n ^O to TE ₀₁ ^O using an advanced periodic wall perturbation technology, the second part is to convert TE ₀₁ ^O to mode basing on the method of gradually changing the wave guide cross section. An example at 37.5Ghz is given. For the first part, the efficiency is 94.71%, the length is 1.868m. For the second part, the theoretic figure of reflectance coefficient vs. frequency is given.     

Specific features of the recombination loss of the photocurrent in n-TiN/p-Si anisotype heterojunctions

Photosensitive n-TiN/p-Si heterostructures are fabricated by reactive magnetron sputtering. The heterostructures generate an open-circuit voltage of V _oc = 0.4 V and a short-circuit current of I _sc = 1.36 mA/cm² under illumination at 80 mW/cm². An analysis of the light current-voltage characteristic and quantum-yield spectrum demonstrate that the poor photoelectric parameters are due to recombination in the base region of the heterojunction and to the formation of a high-resistivity SiO₂ layer on the surface of polycrystalline silicon, which fails to provide high-quality passivation of surface states.     

Plasma oscillations in two-dimensional semiconductor superstructures

The possibility of plasma oscillations occurring in a two-dimensional electron gas with a superstructure was studied taking into account the Umklapp processes. In the case of high temperatures ( where Δ is the width of the conduction miniband and T is temperature expressed in energy units), the dispersion relation ω(k) was obtained. It is shown that, for small values of , the plasmon spectrum features the characteristic dispersion ω² ～ k, which corresponds to a two-dimensional electron gas without a superstructure. For arbitrary values of k, the spectrum is periodic with a period of 2π/d. Numerical estimation of the characteristic frequency of the plasma oscillations for the two-dimensional superstructures currently under experimental investigation yields 10¹³ s^?1.     

Anisotropical electro-polarization effects induced in C2−O bonds present around the α-helixes of silk fibroin

Under the influence of perpendicularly applied positive electro-static field less than ≈10³V/cm to silk fibron textiles, at the high frequency side of the C₂?O bending reflection band (≈450～350 cm^?1), effect of step creation and step annihilation of the C₂?O pseudo dending bands was induced in three stages at ≈600～450 cm^?1 region IR spectroscopically relating to the stepnized statistical transfer of the unbonded 2P₂, π electrons in carbon which present with density of ≈4.0×10¹⁴/cm² in the surface mono-layer of silk fibroin from the states formed in (?C₁?C₂?N?)_m spiral chains upto the pseudo-bending states formed in C₂?O bondings. Fine ≈90 steps measured overlapping on these four types of C₂?O reflection bands were analysed as to consist four step series and they were shown as,y = A·J^m + B cm^?1 with A=20, B=521, m=0.55 and J=1, 2...18 for the B-series. And with A=39, B=283, m=0.63 and J=1, 2 ...17 for the C-series.y _J = A·J + B cm^?1 with A=11.42, B=201 and J=1, 2...13, for the D-series. And, stepnized C₂?O bending bands including that of permanent oscillators and pseudo-bending oscillators induced by the effect of transfer of the unbonded 2P₂ electrons in carbon atoms were shown as, E_N=A·N²+B·N+C (eV) with A=?1.50×10^?3, B=1.65×10^?2 and C=2.4×10^?2.     

Infrared lattice bands of some pearls

From analysis of anisotropical lattice bands properties of ≈50 reflection spectra both of the CO stretching and bending bands measured from some pearl (Ca⁺⁺CO ₃ ^?? or Ca⁺⁺HCO ₃ ^?? layer) we discussed following subjects. i) Quantized properties present both in reflectivity and in energy. ii) classifications of the “Optical Activity”. iii) Polar distributions of the CO₃ oscillators in Ca⁺⁺CO ₃ ^?? surface mono-layer. iv) Force constants of these oscillators. v) Step variation of the dipolemoment and their influences to the degree of “Optical Activity”. vi) Two types of hysteresis loops of the values of Y_N (M_2Jbend (θ)/M_1Jstret. (θ)) derived from the oscillators which are at “innert-state”, at “weak active-state” and at “active-state”.     

Anisotropical C2−O reflection bands measured in α-helixes of silk fibroin

From analysis of 36 anisotropical reflectrion spectra of the C₂?O bending bands of silk fibroin at ≈700～200 cm^?1 region at static state, presence of the A, B, C and D-band and reflection edge was also confirmed. Furthermore, we confirmed stepnized reflectivity overlapping on the C₂?O bending bands and stenized values of the reflection integral (optical activity). Second, analysing four diffusion diagrams of these bands, we inspected stepnized polar distribution of the band and quantized polar distribution was confirmed as, θ^N = 27.5·N + 2.5 (degrees) with N=1, 2, 3, 4...12 and 13, without N=5,6 and 7 at θ=120°～180° as in case of polar distribution of the C₂?O and Si?O stretching reflection bands and C₂?O bending band measured in case of silicate cellulose present in the surface skin layer of bamboo's stem.     

On the theory of anomalous photovoltage in multilayer structures with p-n junctions

Steady-and nonsteady-state photovoltages appearing in a multilayer structure with p-n junctions under the conditions of nonuniform illumination are considered for an arbitrary ratio between the diffusion length L and the sizes d of the p-and n-regions. It is shown that, for , the photovoltage is substantially lower (by d ²/12L ² times) than in the case of owing to the mutual influence of neighboring p-n junctions. Relaxation of the photovoltage is controlled by recharging of the barrier capacitances of p-n junctions, and the relaxation time exceeds by several orders of magnitude the lifetime of nonequilibrium charge carriers in the p-and n-regions. The results obtained make it possible to explain the special features of the effect of anomalous photovoltage in polycrystalline films.     

p +-Si/nano-SiO2/n +-Si capacitor-based tunnel diode with negative differential resistance and a quartz resonator

To demonstrate the extending functionality of the simplest MOS (metal-oxide-semiconductor) capacitor, a structure with a p ⁺-Si/nano-SiO₂ heterojunction in which strongly degenerate n ⁺-Si is used instead of a metal electrode is considered. As a result, a tunnel diode with negative differential resistance and a quartz resonator is obtained. Its electrical characteristics are superior to those of the corresponding Esaki diode and are controlled not only by the Silicon doping level, but also by the SiO₂ thickness.     

High resolution molecular spectroscopy in the submillimeter region

Fourier Transform laboratory measurements have been carried out, for the first time in the 8–85 cm^?1 spectral region, with an unapodized resolution of 3.3. 10^?3 cm^?1 and a frequency accuracy of 2. 10^?4 cm^?1. Samples from spectra of several molecules namely: CO, O₃, H₂O₂, NO, NO₂, HNO₃, SO₂, H₂S, HOCL, NOCL, HNCO, ND₃ and AsH₃ are presented to show both the quality of the measurements and the type of information supplied by high resolution spectroscopy in the submillimeter region.     

Point quantum contacts in disordered Si MOS structures with an inversion p-type channel: Nonlinear behavior of the system in the longitudinal and transverse electric fields

The behavior of the lateral conductance G of mesoscopic Si-MOS structures with an inversion p-type channel and a high concentration of built-in charges of ions (N _t≤3×10¹²cm^?2) in the conditions of the insulator-metal percolation transition is discussed. The following features are observed in the dependences of G on the transverse (V _g) and longitudinal (V _d) voltages at temperatures ≥77 K: a quasi-plateau G(V _g) at G ≈ 2e ²/h and a minimum G(V _d) at . It is shown that the data obtained from the field effect are consistent with the results of calculations of the characteristics of the point quantum contact (the curvature parameters for the potential in the longitudinal and transverse directions are ?ω _x ≈ ?ω _y ≈ 10 meV) but are completely inconsistent with the value of ?ω _x ≈ 300 meV determined from the dependence G(V _d). This discrepancy is related to nonlinearity of a system of quantum contacts with respect to the longitudinal and transverse electric fields. It is shown that the number of quantum contacts along the percolation path varies in the range 1 ≤ N ≤ 30 under the effect of an electric field.     

Ion-beam synthesis of InSb nanocrystals in the buried SiO2 layer of a silicon-on-insulator structure

The ion-beam synthesis of InSb nanocrystals in the buried SiO₂ layer of a silicon-on-insulator structure is investigated. The distributions of In and Sb atoms after annealing at a temperature of T _a = 500–1100°C are studied. It is established that the redistribution of implanted atoms is unsteadily dependent on the annealing temperature. The formation of InSb nanocrystals occurs at Ta ≥ 800°C near the Si/SiO₂ interface and at a depth corresponding to the mean paths R _p . Analysis of the profiles of implanted atoms and of the structure and depth distribution of nanocrystals formed allows an inference regarding the two-stage character of formation of the InSb phase. In the initial stage, antimony precipitates are formed; further the precipitates serve as nuclei for indium and antimony to flow to them.     

The Improvement of Electrical Characteristics of Pt/Ti Ohmic Contacts to Ga-Doped ZnO by Homogenized KrF Pulsed Excimer Laser Treatment

We investigated the effect of KrF excimer laser surface treatment on Pt/Ti ohmic contacts to Ga-doped n-ZnO (N_d = 4.3 × 10¹⁷ cm^?3). The treatment of the n-ZnO surfaces by laser irradiation greatly improved the electrical characteristics of the metal contacts. The Pt/Ti ohmic layer on the laser-irradiated n-ZnO showed specific contact resistances of 2.5 × 10^?4 ～ 4.8 × 10^?4 Ω cm² depending on the laser energy density and gas ambient, which were about two orders of magnitude lower than that of the as-grown sample, 8.4 × 10^?2 Ω cm². X-ray photoelectron spectroscopy and photoluminescence measurements showed that the KrF excimer laser treatments increased the electron concentration near the surface region of the Ga-doped n-ZnO due to the preferential evaporation of oxygen atoms from the ZnO surface by the laser-induced dissociation of Zn-O bonds.     

Interaction of infrared radiation with free carriers in mesoporous silicon

Features of absorption and reflection of infrared radiation in the range 500–6000 cm^?1 are investigated; these features are associated with free carriers in the layers of mesoporous Si (porosity, 60–70%) formed in single-crystal p-Si(100) wafers with a hole concentration of N _p ≈10²⁰ cm^?3. It is found that the contribution of free holes to the optical parameters of the samples decreases as the porosity of the material increases and further falls when the samples are naturally oxidized in air. The experimental results are explained in the context of a model based on the Bruggeman effective medium approximation and the Drude classical theory with a correction for additional carrier scattering in silicon residues (nanocrystals). A comparison between the calculated and experimental dependences yields a hole concentration in nanocrystals of N _p ≈10¹⁹ cm^?3 for as-prepared layers and shows a reduction of N _p when they are naturally oxidized.     

Electrical properties of Zinc-Tin diarsenide (ZnSnAs<Subscript>2</Subscript>) irradiated with H<Superscript>+</Superscript> ions

The results of studying the electrical properties and isochronous annealing of p-ZnSnAs₂ irradiated with H⁺ ions (energy E = 5 MeV, dose D = 2 × 10¹⁶ cm^?2) are reported. The limiting electrical characteristics of irradiated material (the Hall coefficient R _H (D)_lim ≈ ?4 × 10³ cm³ C^?1, conductivity σ (D)_lim ≈ 2.9 × 10^?2 Ω^?1 cm^?1, and the Fermi level position F _lim ≈ 0.58 eV above the valence-band top at 300 K) are determined. The energy position of the “neutral” point for the ZnSnAs₂ compound is calculated.     

Raman and infrared spectroscopy of GaN nanocrystals grown by chloride-hydride vapor-phase epitaxy on oxidized silicon

Raman and infrared spectroscopy were applied to study nanocrystalline GaN films grown by chloride-hydride vapor-phase epitaxy on SiO₂/Si(111) substrates at T=520°C. It was ascertained that GaN nanocrystals are formed on the oxidized silicon surface at a rate of 10^?2 nm/s. It was shown that the peaks in the Raman spectra E₂(high)=566 cm^?1 and A₁(LO)=730 cm^?1 correspond to the elastically strained GaN wurtzite structure. It was detected that a peak related to E₁(TO)=558 cm^?1 arises in the infrared spectra, which shows that elastic stresses in the nanocrystals are insignificant.     

Low-temperature (77 K) impurity breakdown in <Emphasis Type="Italic">p</Emphasis>-type 4<Emphasis Type="Italic">H</Emphasis>-SiC

The impact ionization of acceptors in aluminum-doped 4H-SiC epitaxial films (Al concentration 2 × 10¹⁵ cm^?3) at a temperature of 77 K is studied. It is found that the impact-ionization coefficient exponentially depends on the reverse electric field: α _p = α*_pexp(?F*/F). The largest ionization coefficient is α* _p = 7.1 × 10⁶ cm^?3 s^?1, and the threshold field is F* = 2.9 × 10⁴ V/cm.