Thermostimulated conductivity of synthetic semiconductor diamonds doped with boron during synthesis

The properties of diamond as a new material for semiconductor electronics have been studied insufficiently at present. One of the most powerful techniques for study of impurity centers is the method of thermostimulated conductivity (TSC).Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 130–132, September, 1978.In conclusion, the authors thank Yu. M. Eotner for providing the synthetic semiconductor diamond specimens for measurement.     

Current-voltage characteristics of synthetic semiconductor diamonds doped with boron during synthesis

Current-voltage characteristics (CVC) of synthetic semiconductor diamonds are presented. In certain low-resistance specimens at definite temperature intervals an N-type CVC is found. Investigations performed permit a qualitative explanation of the majority of CVC peculiarities, and determination of the boron acceptor impurity activation energy E_a = 0.36 eV.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 7–12, September, 1978.In conclusion the authors thank Yu. M. Rotner for presenting the synthetic semiconductor diamonds which were studied.     

Formation of precipitates in heavily boron doped 4H-SiC

Secondary ion mass spectrometry (SIMS) and transmission electron microscopy (TEM) are utilized to study precipitation and the solubility of B in 4H-SiC epitaxial layers super saturated with B. Heat treatments are performed in Ar atmosphere in an rf-heated furnace at temperatures between 1700 and 2000 °C. SIMS ion images, and TEM micrographs reveal the formation of two types of precipitates where the larger, more thermally stable one is suggested to be B₄C. The boron solubility is determined from SIMS depth profiles and is shown to follow the Arrhenius expression: 7.1 × 10²² exp(−1.4 eV/k_BT) cm⁻³ over the studied temperature range.     

Infra-red properties of bulk heavily doped silicon

Summary In 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.

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Riassunto In 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.

     

Optical properties of laser-induced heavily doped Si

An analysis of recently reported experimental studies⁽¹⁾ of the optical properties of laser-induced heavily doped Si layers is presented here. The analysis has been made on the basis of models like those of Penn⁽²⁾ and Breckenridge et al.⁽³⁾ Our calculations show that, in general, N_eff, the effective number of electrons contributing to optically induced electronic transitions, increases as does ε₂(E), the imaginary part of the complex dielectric constant. This reflects an increased absorption coefficient for these As-doped samples. These studies have been carried out on samples of Si heavily doped by ion-implantation followed by a laser-annealing process. The conclusions based on these studies are seen to be in accord with those of Aspnes et al.⁽⁴⁾ and Vina and Cardona.⁽⁵⁾     

Transport properties of heavily AsF5 doped polyacetylene

We report measurements of the temperature dependence of the thermoelectric power and electrical conductivity for polyacetylene heavily doped (more than 10%) with arsenic pentafluoride. The thermopower is small, positive and linear with temperature. The conductivity is very large for a polymeric system, about 1000 (Ω cm)^-1 at room temperature, and as temperature is decreased drops in value by less than a factor of two, becoming essentially temperature independent below 4 K. The samples exhibited ohmic behavior at the current densities used and did not show any frequency dependence up to 1000 Hz. No evidence for superconductivity was found down to 30 mK. The results are interpreted as the first conclusive evidence for the existence of a metallic state at all temperatures in this material.     

Ion-beam studies of synthetic single-crystal diamonds

A surface layer of polished single-crystal diamond plates with the (100) orientation, which can be applied to planar high-frequency high-power microstructures, is investigated by means of ion-beam and X-ray methods. It is demonstrated that the diamond plates are characterized by a high degree of structural perfection and a low level of surface roughness.     

Electronic structure of boron nitride nanostructures doped with a carbon atom

We have investigated, using first-principles calculations, the role of a substitutional carbon atom on the electronic properties of boron nitride monolayers, nanotubes, and nanocones. It is shown that electron states in the energy-gap are independent of the curvature, being the same for the monolayer, for the cone and for the tube. It is also found, that the presence of carbon in the boron nitride compounds induces a spin polarization, with magnetic moment of 1.0 μ_B, which does not depend on the curvature.     

Electronic properties of boron nanotubes with axial strain

The electronic properties of boron nanotubes with axial strain are investigated by first principle calculations. The band gaps of the (3, 3) and (5, 0) boron nanotubes are found to be modified by axial strain significantly. We find that the semiconductor-metal transition occurs for the (3, 3) boron nanotubes with both compressive and tensile strain. While for the (5, 0) boron nanotubes, only the tensile strain induces the semiconductor-metal transition. These boron nanotubes have the largest gaps under compressive strain.      

Synthesis and characterizations of boron and nitrogen co-doped high pressure and high temperature large single-crystal diamonds with increased mobility

We synthesized and investigated the boron-doped and boron/nitrogen co-doped large single-crystal diamonds grown under high pressure and high temperature (HPHT) conditions (5.9 GPa and 1290℃). The optical and electrical properties and surface characterization of the synthetic diamonds were observed and studied. Incorporation of nitrogen significantly changed the growth trace on surface of boron-containing diamonds. X-ray photoelectron spectroscopy (XPS) measurements showed good evident that nitrogen atoms successfully incorporate into the boron-rich diamond lattice and bond with carbon atoms. Raman spectra showed differences on the as-grown surfaces and interior between boron-doped and boron/nitrogen co-doped diamonds. Fourier transform infrared spectroscopy (FTIR) measurements indicated that the nitrogen incorporation significantly decreases the boron acceptor concentration in diamonds. Hall measurements at room temperature showed that the carriers concentration of the co-doped diamonds decreases, and the mobility increases obviously. The highest hole mobility of sample BNDD-1 reached 980 cm²·V^-1·s^-1, possible reasons were discussed in the paper.     

Implantation site of boron in heavily doped silicon: A β-NMR study

Using β-NMR with¹²B as nuclear probes the temperature dependence of the lattice-site occupation of boron implanted into heavily doped silicon is studied. In p-type material the unperturbed substitutional fraction of¹²B increases from 10% at 300 K to ≃40 % at 950 K. In n-type material this fraction starting from 20% at 300 K approaches the saturation value of ≃80 % at 600 K already. This behaviour suggests that the site of implanted boron in silicon is controlled by the Fermi level.     

Electronic properties of boron and nitrogen doped graphene nanoribbons and its application for graphene electronics

On the basis of density functional theory calculations, we have systematically investigated the electronic properties of armchair-edge graphene nanoribbons (GNRs) doped with boron (B) and nitrogen (N) atoms. B (N) atoms could effectively introduce holes (electrons) to GNRs and the system exhibits p- (n-) type semiconducting behavior after B (N) doping. According to the electronic structure calculations, Z-shape GNR-based field effect transistors (FETs) is constructed by selective doping with B or N atoms. Using first-principles quantum transport calculations, we demonstrate that the B-doped p-type GNR-FETs can exhibit high levels of performance, with high ON/OFF ratios and low subthreshold swing. Furthermore, the performance parameters of GNR-FETs could be controlled by the p-type semiconducting channel length.     

Electronic properties of graphene nanoribbon doped by boron/nitrogen pair: a first-principles study

By using the first-principles calculations, the electronic properties of graphene nanoribbon (GNR) doped by boron/nitrogen (B/N) bonded pair are investigated. It is found that B/N bonded pair tends to be doped at the edges of GNR and B/N pair doping in GNR is easier to carry out than single B doping and unbonded B/N co-doping in GNR. The electronic structure of GNR doped by B/N pair is very sensitive to doping site besides the ribbon width and chirality. Moreover, B/N pair doping can selectively adjust the energy gap of armchair GNR and can induce the semimetal-semiconductor transmission for zigzag GNR. This fact may lead to a possible method for energy band engineering of GNRs and benefit the design of graphene electronic device.     

Some properties of the fluorescence spectra of heavily doped ruby

Fluorescent spectra and decay times were obtained with single crystals of Al₂O₃, Cr-doped in the range 0.05 to 5.0% in atomic weight. At 77 K the R and N lines of very heavily doped ruby have two decay times (0.39 and 0.08 ms for a 3 wt% sample). The decay curves obtained in the wavelength region of a broad band centered at about 771 nm are characterized by one decay time (0.30 ms for the 3 wt% sample at 77 K). It is suggested that this band is partly due to an energy-transfer mechanism associated with Cr clusters.     

掺杂六角形石墨烯电子输运特性的研究

锯齿型和扶手椅型六角形石墨烯分别跨接在两Au电极上, 构成分子纳器件, 同时考虑对六角形石墨烯分别进行B, N和BN局部规则掺杂. 利用第一性原理方法, 系统地研究了这些器件的电子输运特性. 计算结果表明: B及BN掺杂到扶手椅型六角形石墨烯, 对其电流有较好的调控效应, 同时发现本征及掺杂后的锯齿型六角形石墨烯均表现为半导体性质, 且N及BN掺杂时, 表现出明显的负微分电阻现象, 特别是N掺杂的情况, 能呈现显著的负微分电阻效应, 这也许对于发展分子开关有重要应用. 通过其透射特性及掺杂诱发的六角形石墨烯电子结构的变化, 对这些结果的内在原因进行了说明.     

Electronic transport properties of single-wall boron nanotubes

Electronic transport properties of single-wall boron nanotube(BNT) with different chiralities, diameters, some of which are encapsulated with silicon, germanium, and boron nanowires are theoretically studied. The results indicate that the zigzag(3, 3) BNT has more electronic transmission channels than the armchair(5, 0) BNT because of its unique structure distortion. Nanowires encapsulated in the BNT can enhance the conductance of the BNT to some extent by providing a significant electronic transmission channel to the BNT. The effect of the structure of nanowires and the diameter of BNTs on the transport properties has also been discussed. The results of this paper can enrich the knowledge of the electron transport of the BNT and provide theoretical guidance for subsequent experimental study.     

Electronic structure and optical property of boron doped semiconducting graphene nanoribbons

We present a system study on the electronic structure and optical property of boron doped semiconducting graphene nanoribbons using the density functional theory. Energy band structure, density of states, deformation density, Mulliken popular and optical spectra are considered to show the special electronic structure of boron doped semiconducting graphene nanoribbons. The C—B bond form is discussed in detail. From our analysis it is concluded that the Fermi energy of boron doped semiconducting graphene nano...