Investigation of surface potential in the V-defect region of MBE CdxHg1−xTe film

Atomic-force microscopy is used to investigate the distribution of the contact-potential difference (surface potential) in Cd x Hg1 − x Te epitaxial films grown by molecular-beam epitaxy. Modification of the solid-solution composition near the V-defect results in a variation in the contact-potential difference. It is shown that the solid-solution composition varies by ∼0.05 (2.5 at %) towards increasing mercury content in the V-defect region, and a region of mercury depletion by 0.36 at % is observed at the V-defect periphery. From analysis of the surface-potential distribution, it is shown that the Cd x Hg1 − x Te epitaxial film contains unform V-defects with a diameter less than 1 μm in addition to macroscopic V-defects

The laser-induced electron-hole liquid in the diamond: critical lattice temperature and non-equilibrium carrier density

Integrated photoluminescence spectra of two diamond samples under laser radiation excitation at 193 and 222 nm, depending on the temperature in the range of 80-300 K and the peak intensity in the range of 7-13 MW/cm2, were investigated. At temperatures below 200 K, and the peak intensity of more than 10 MW/cm2 of laser radiation at 222 nm, the radiative recombination band of electron-hole liquid was observed in integrated photoluminescence spectra of CVD diamond sample. © (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only

Changes in the electro-physical properties of MCT epitaxial films affected by a plasma volume discharge induced by an avalanche beam in atmospheric-pressure air

In this paper the influence of the plasma volume discharge of nanosecond duration formed in a non-uniform electric field at atmospheric pressure on samples of epitaxial films HgCdTe (MCT) films are discussed. The experimental data show that the action of pulses of nanosecond volume discharge in air at atmospheric pressure leads to changes in the electrophysical properties of MCT epitaxial films due to formation of a near-surface high- conductivity layer of the n-type conduction. The preliminary results show that it is possible to use such actions in the development of technologies for the controlled change of the properties of MCT

Electro-physical characteristics of a HgCdTe epitaxial films upon exposure by a volume discharge in air at atmospheric pressure

In this paper the influence of the volume discharge of nanosecond duration formed in a non-uniform electric field at atmospheric pressure on samples of epitaxial films HgCdTe (MCT) of p-type conductivity. It is suggested that after exposure on film surface oxide layer was formed. This layer has a built positive charge that leads to the formation of an inversion layer which "shunts" the rest of the sample so that the measured field dependence of Hall coefficient corresponds to the material of n-type of conductivity

The impact of the plasma volume discharge in the atmospheric-pressure air on the distribution of the surface potential in a V-defect region of epitaxial HgCdTe films

In the present report we demonstrate the experimental data obtained as a result of studying the impact of nanosecond plasma volume discharge in the atmospheric-pressure air on the distribution of the surface potential in the V-defect regions of epitaxial HgCdTe films. The experimental data obtained for the variation of the contact potential difference (ΔCPD) between the V-defect and the main matrix of the epitaxial film show that the mean value of ΔCPD for the original surface differs from the one for the irradiated surface for 55 eV. At the same time the mean value of ΔCPD changes its sign indicating that the original surface of the epitaxial HgCdTe film predominantly contains the grains with increased cadmium content while after the irradiation the grains possess an increased content of mercury. Therefore, during the irradiation process a decrease of the mercury content in the near-surface region of the semiconductor takes place resulting in the alteration of the electrophysical properties in the film's near-surface region

Influence of plasma volume discharge in atmospheric-pressure air on the admittance of MIS structures based on MBE p-HgCdTe

This article investigates the effect of a nanosecond plasma volume discharge, which is formed in an inhomogeneous electrical field at atmospheric pressure, on the electrical properties of MIS structures based on HgCdTe (MCT) epitaxial films. The MIS structure based on films exposed to the discharge significantly changed its main parameters. The most notable feature of the structure exposed to discharge is the significant increase in the positive fixed charge in the insulator. A possible reason for changes in the characteristics of MIS structure after exposure to discharge is the significant change in the impurity-defect system of the semiconductor near the interface. This is accompanied with a formation of an insulator film of nanometer thickness on the surface, which gives rise to positive fixed charge

Influence of complex impact of the picosecond electron beam and volume discharge in atmospheric-pressure air on the electronic properties of MCT epitaxial films surface

In the present report we studied the distribution of surface potential of the HgCdTe epitaxial films grown by molecular beam epitaxy after the impact of picosecond electron beam and volume discharge in atmospheric-pressure air. The surface potential distribution was studied by the Kelvin Force Probe Microscopy. The experimental data obtained for the variation of the contact potential difference (ΔCPD) between the V-defect and the main matrix of the epitaxial film. The investigation of the origin epitaxial films show that variation of the spatial distribution of surface potential in the V-defect region can be related to the variation of the material composition. The experimental data obtained for the irradiated samples show that the mean value of ΔCPD for the original surface differs from the one for the irradiated surface for 55 eV. At the same time the mean value of ΔCPD changes its sign indicating that the original surface of the epitaxial HgCdTe film predominantly contains the grains with increased cadmium content while after the irradiation the grains possess an increased content of mercury. Therefore, during the irradiation process a decrease of the mercury content in the near-surface region of the semiconductor takes place resulting in the alteration of the electrophysical properties in the films near-surface region. © (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only

Applied optical properties of diamond

In our paper we report about the optical properties of diamonds having applied sense. Radiation destruction manifests itself in the form of absorption bands and luminescence of vacancies and interstitials. The charge state of the NV centers depends on the impurity-defective composition of the sample. Accelerated particles lose their energy to Cherenkov radiation. The fine splitting of the free exciton state affects the absorption and luminescence spectra in the recombination bands of free excitons and their condensed stat

Fatherhood and unemployment: Involvement characteristics and family relations

Esta pesquisa buscou verificar as características e os fatores significativos do envolvimento paterno em famílias com pais desempregados com filhos em idade escolar, considerando os aspectos sociodemográficos, o relacionamento familiar e os sintomas depressivos do pai. A amostra foi constituída por 188 homens usuários do FGTAS (Fundação Gaúcha de Trabalho e Ação Social) – (SINE) dos municípios de São Leopoldo/RS e de Porto Alegre/ RS. A maioria dos pais estava há três meses desempregada, casados ou com união estável e com idade entre 20 e 56 anos. A coleta de dados incluiu o Inventário Sociodemográfico, o Inventário de Práticas Parentais, Inventário de Depressão Beck e o Familiograma. Ao considerar o envolvimento paterno, verificou-se que fatores como grau de escolaridade e recebimento de ajuda financeira estavam associados ao maior envolvimento do pai com os filhos. Um grau mais alto da afetividade do pai na relação com a esposa e com o filho também resultou em maior envolvimento parental. Em contrapartida, pais deprimidos tinham mais conflitos com esposa e filho, confirmando a importância do estado emocional para a qualidade das relações familiares. Os resultados encontrados refletem a necessidade de políticas públicas voltadas para o atendimento dos trabalhadores em situação de desemprego e suas famílias. As condições de enfrentamento dessa situação adversa dependem do suporte emocional e financeiro que a rede de apoio familiar poderá proporcionar ao pai durante esse período. Palavras-chave: envolvimento paterno, depressão, desemprego.This research sought to verify the characteristics and significant factors of paternal involvement in families with unemployed fathers of school age children, regarding sociodemographic aspects, family relationships and father’s depressive symptoms. The sample consisted of 188 men, users of the employment agency FGTAS (Fundação Gaúcha de Trabalho e Ação Social) – SINE of São Leopoldo/RS and Porto Alegre/RS. The majority of the fathers had been unemployed for three months, married or in a stable relationship, age between 20 and 56 years old. Data collection included Socio Demographic Inventory, Father Involvement Inventory, Beck Depressive Inventory and the Familiogram. Regarding father involvement, it was observed that factors such as level of education, financial help and helping family income through temporary jobs were associated with greater involvement with children. A more affective relationship with the wife and children also resulted in greater father involvement. In turn, depressed fathers had more conflict with wife and child, confirming the importance of emotional state to the quality of family relations. The findings reflect the need of public policies geared to assist workers and their families in unemployment situation. Conditions to deal with this adverse situation rely on emotional and financial support that family net will be able to provide to fathers during this period of time. Key words: father involvement, depression, unemployment

Influence of pulsed nanosecond volume discharge in atmospheric-pressure air on the electrical characteristics of MCT epitaxial films

The purpose of this paper was investigating the effect of volume nanosecond discharge in air at atmospheric pressure on the electro-physical properties of the HgCdTe (MCT) epitaxial films grown by molecular beam epitaxy. Hall measurements of electro-physical parameters of MCT samples after irradiation have shown that there is a layer of epitaxial films exhibiting n-type conductivity that is formed in the near-surface area. After more than 600 pulses of influence parameters and thickness of the resulting n-layer is such that the measured field dependence of Hall coefficient corresponds to the material of n-type conductivity. Also it is shown that the impact of the discharge leads to significant changes in electro-physical characteristics of MIS structures. This fact is demonstrated by increase in density of positive fixed charge, change in the hysteresis type of the capacitance-voltage characteristic, an increase in density of surface states. The preliminary results show that it is possible to use such actions in the development of technologies of the controlled change in the properties of MCT. © (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only