[en] Graphene is experienced its golden age in the world of nanotechnology. Despite the fact that it takes key roles in the very complex areas, it is a simple two-dimensional material which is formed by only carbon atoms with a honeycomb form on especially another material. Graphene monolayer is usually supported by a known SiC substrate. SiC is a valuable material for both electronics and nuclear researches because of the excellent shielding and conduction properties. We simulated 500 keV proton irradiation effects on bilayer graphene on SiC by SRIM code in this paper. SRIM is a very detailed code capable of modeling ranging from very thick materials to single layer structures. This code is based on sending ions with specific energy to a target material. We presented damages and displacements caused by 500 keV protons to bilayer graphene/SiC target in the view of promising face of space and solar cell technology. (author)

[en] Elemental concentrations of five different seed coats of fruit seeds were determined by using wavelength-dispersive X-ray fluorescence (WDXRF) technique. Basic aim of this study is to measure mass percentages of macro, micro and trace elements in samples. Besides, analyze results have been commented in terms of correlation between the same element types in seed coats of different fruits. Some interesting results have been obtained about element quality and quantity. (author)

[en] Sputtered Cr/n-GaAs Schottky diodes have been prepared and annealed at 200 and 400 deg. C. The current-voltage (I-V) characteristics of the as-deposited and annealed diodes have been measured in the temperature range of 60-320 K with steps of 20 K. The effect of thermal annealing on the temperature-dependent I-V characteristics of the diodes has been investigated experimentally. The ideality factor and barrier height (BH) values for 400 deg. C annealed diode approximately remain unchanged from 120 to 320 K, and those of the as-deposited sample from 160 to 320 K. The departures from ideality at low temperatures have been ascribed to the lateral fluctuations of the BH. The BH values of 0.61 and 0.74 eV for the as-deposited and 400 deg. C annealed diodes were obtained at room temperature, respectively. A Richardson constant value of 9.83 A cm^-2 K^-2 for 400 deg. C annealed Schottky diode, which is in close agreement with the known value of 8.16 A cm^-2 K^-2 for n-type GaAs. Furthermore, T₀ anomaly values of 15.52, 10.68 and 5.35 for the as-deposited and 200 and 400 deg. C annealed diodes were obtained from the nT versus T plots. Thus, it has been seen that the interface structure and quality improve by the thermal annealing at 400 deg. C.

[en] We have fabricated two groups of Cr/n-GaAs Schottky diodes (SDs) by magnetron sputtering technique to determine whether T₀ anomaly varies in similarly fabricated SDs or not. Firstly, the first group diodes were inserted into a vacuum chamber to form the Schottky contacts, then the second group diodes which are held in the clean room medium for 3 h before Schottky metal deposition. The current-voltage (I-V) characteristics of three diodes (the dots of the sample CrD1) from the first group and two diodes (the dots of the sample CrD2) from the second group were measured in temperature range of 60-320 K. The barrier heights increased with increasing temperature in range of 60-160 K, and did not changed in range of 160-320 K. Ideality factory value decreased with increasing temperature in range of 60-160 K and changed between 1.05 and 1.10 in range of 160-320 K. T₀ anomaly values were calculated from straight lines fitted to nT'-T plots. The fits to the experimental values of nT-T plots are parallel to the ideal Schottky contact line, especially for the dots (Schottky diodes) of the sample CrD1. T₀ anomaly values for the dots of the sample CrD1 were obtained as 13.9, 11.20 and 13.31 K; and the values of 19.74 and 19.20 K was obtained for the dots of the sample CrD2. It has been concluded that the T₀ anomaly values for the similarly fabricated diodes (the dots of the sample CrD1 or the CrD2) are almost very close to each other within the margins of experimental error

[en] The macroscopic cross-section Σ and average neutron fluence in matter Φ are usable factors to comment neutron shielding property of samples. In this paper, we have used MgB₂, NaBH₄ and KBH₄ samples including different percentages of boron. Neutron macroscopic cross-section measurements of them have been done by using a source of mono-energetic neutrons (E_eff = 4.5 MeV ²⁴¹Am-Be). Average neutron fluence values and double differential fast neutron flux distributions of each samples calculated by using FLUKA Monte Carlo code. Also half value layers (HVLs) of samples are compared to paraffin which is one of the most neutron moderators. As a result, growing boron concentration can raise neutron shielding property of materials. (author)