ABSTRACT
The GaAs semiconductor structures for the application as betavoltaic power sources were investigated. Three types of structures underwent a comparative study: a Schottky diode, a p-n junction and Schottky structure modified by deposition of a carbon layer. The power characteristics were estimated by Monte-Carlo simulation and collected current calculation using parameters obtained from the electron beam induced current technique. It was shown that carbon deposition on the top of n-GaAs allows passivating the surface states and thus improving betavoltaic performance.
ABSTRACT
In this work the crystal structure by single crystal X-ray measurement and optical properties of 1D propane-1,2-diammonium pentachlorobismuthate [NH3CH2CH(NH3)CH3]BiCl5 organic-inorganic hybrid perovskite are presented. It is prepared by mixing ethanolic solution of equimolar ratios (1:1) of its basic components. The title compound crystallized in the noncentrosymmetric orthorhombic space group Pca21 with Z = 8 molecules per unit cell. The unit-cell parameters are a = 19.8403â (7)â Å, b = 6.3303â (2)â Å, c = 19.0314â (7)â Å. The vibrational spectra are studied by Raman and infrared spectroscopy. The optical properties show a strong absorption in the ultraviolet region, the band gap energy Eg is found to be 3.15â eV. Cathodoluminescence measurements are also discussed.
ABSTRACT
A bulk nanostructured material based on oxidized silicon nanopowder was fabricated using a spark plasma sintering technique. Structural investigations revealed that this material has the composition of â¼14 nm core Si granules inside an SiO2 shell. Photoluminescence measurements have shown that the emission spectra lie in the energy range of 0.6-1.1 eV, which is not typical of the emissions of the Si/SiO2 nanostructures reported in numerous papers. This result can be explained by the formation of energy states in the bandgap and the participation of these states in both electronic transport and photoluminescence emission. Annealing of the sample leads to a decrease in defect density, which in turn leads to quenching of the 0.6-1.1 eV photoluminescence. In this case â¼1.13 eV inter-band transitions in the Si core start to play a dominant role in radiative recombination. Thus, the possibility of controlling the photoluminescence emission over a broad wavelength range was demonstrated.
ABSTRACT
A verification of the Monte Carlo simulation software for the prediction of short circuit current value is carried out using the Ni-63 source with the activity of 2.7â¯mCi/cm2 and converters based on Si p-i-n diodes and SiC and GaN Schottky diodes. A comparison of experimentally measured and calculated short circuit current values confirms the validity of the proposed modeling method, with the difference in the measured and calculated short circuit current values not exceeding 25% and the error in the predicted output power values being below 30%. Effects of the protective layer formed on the Ni-63 radioactive film and of the passivating film on the semiconductor converters on the energy deposited inside the converters are estimated. The maximum attainable betavoltaic cell parameters are estimated.
ABSTRACT
In the paper a manufacturing process of three-dimensional (3D) microchannel structure by silicon (Si) anodic etching was discussed. The possibility of microchannels formation allows to increase the active area more than 100 times. In this structure the p-n junction on the whole Si surface was formed. The obtained data allowed to evaluate the characteristics of the betavoltaic converter with a 3D structure by using isotope 63Ni with a specific activity of 10Ci/g.
ABSTRACT
The x-ray beam induced current method (XBIC) is realized on the laboratory x-ray source using the polycapillary x-ray optics. It is shown that rather good images of grain boundaries in Si can be obtained by this method. The parameters of x-ray beam are estimated by the simulation of Schottky diode image. A good correlation between the experimental and calculated grain boundary XBIC contrast is obtained. The possibilities of laboratory source based XBIC method are estimated.