<span style="font-size:10.0pt;font-family: "Times New Roman";mso-fareast-font-family:"Times New Roman";mso-bidi-font-family: Mangal;mso-ansi-language:EN-US;mso-fareast-language:EN-US;mso-bidi-language: HI" lang="EN-US">Measurement of <span style="font-size:10.0pt;font-family: Symbol;mso-fareast-font-family:"Times New Roman";mso-bidi-font-family:Mangal; mso-ansi-language:EN-US;mso-fareast-language:EN-US;mso-bidi-language:HI" lang="EN-US">g<span style="font-size:10.0pt;font-family:"Times New Roman";mso-fareast-font-family: "Times New Roman";mso-bidi-font-family:Mangal;mso-ansi-language:EN-US; mso-fareast-language:EN-US;mso-bidi-language:HI" lang="EN-US">-ray transmission factors of semiconductor crystals at various<span style="font-size:10.0pt;font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";mso-bidi-font-family:Mangal; mso-ansi-language:EN-NZ;mso-fareast-language:EN-US;mso-bidi-language:HI" lang="EN-NZ"> annealing<span style="font-size:10.0pt;font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";mso-bidi-font-family:Mangal; mso-ansi-language:EN-US;mso-fareast-language:EN-US;mso-bidi-language:HI" lang="EN-US"> temperature and time </span></span></span></span></span>

49-55In the present study,<b style="mso-bidi-font-weight: normal"> the change according to the annealing temperature and time of g-ray transmission factors or transmissivity of InSe, InSe:Sn semiconductor crystals that prepared by not evaporated onto the stage (glass) and InSe, InSe:Mn, InSe:Fe, InSe:Ag, InSe:Cd, InSe:Sn and InSe:Gd semiconductor crystals that prepared by evaporated onto the stage (glass), have been examined. Gamma-rays of 241Am passed through crystals have been detected by a high-resolution Si(Li) detector and by using energy dispersive X-ray fluorescence spectrometer (EDXRF). Undoped-InSe and Mn, Fe, Ag, Cd, Sn, Gd doped InSe semiconductor crystals have been grown by using the Bridgman/Stockbarger. Evaporated onto the stage crystals have been prepared by using thin-film coatings system with thermal evaporation method. The structural and lattice parameters of the InSe and InSe:Sn semiconductors have been analyzed by using X-ray diffractometer (XRD). Transmission factors have been given graphically against the <span style="mso-ansi-language: EN-NZ" lang="EN-NZ">annealing temperature and time for time range 0 (unannealed)-60 min with a step of 10 min. Also, transmission factors have been measured for annealing temperature range 50-(combustion temperature of the crystal) with a step of 50°C for not evaporated onto the stage semiconductor crystals. Transmission factors have been measured for annealing temperature range 60<span style="font-family:Symbol;mso-ascii-font-family: " times="" new="" roman";mso-hansi-font-family:"times="" roman";mso-char-type:symbol;="" mso-symbol-font-family:symbol"="" lang="EN-GB">°C-(cracking temperature of the stage) with a step of 60<span style="font-family:Symbol;mso-ascii-font-family: " times="" new="" roman";mso-hansi-font-family:"times="" roman";mso-char-type:symbol;="" mso-symbol-font-family:symbol"="" lang="EN-GB">°C for evaporated onto the stage crystals. Results are presented and discussed in the present paper. </span

Evaluation of structural and optical properties of Mn-Doped ZnO thin films synthesized by Sol-Gel technique

Turgut, Guven/0000-0002-5724-516X; Dogan, Seydi/0000-0001-9785-4990; GURBULAK, BEKIR/0000-0002-5343-4107WOS: 000311511300019Undoped ZnO and Mn-doped ZnO (MZO) films with 0.25, 0.50, and 0.75 mol pct were synthesized onto glass substrates by sol-gel spin-coating technique, and the effects of Mn on structural, morphologic, and optical properties were investigated. the XRD results indicate that the films have wurtzite structure with polycrystalline nature. However, the dominant peak was (002) diffraction peak for all samples; other diffraction peaks with less intensity such as (100), (101), (102), (110), (103), (112), and (004) were observed for the undoped ZnO. the lattice parameter values of MZO thin films were lower than that of the undoped ZnO. Plane stress values indicated that the films had the tensile stress. A decrease in the grain sizes was observed with the increasing Mn mole percent. the optical transmission values were found to be 82 pct for the undoped ZnO and 80, 78, and 75 pct for the MZO with 0.25, 0.50, and 0.75 mol pct, respectively, at the wavelength of 405 nm. the optical band gap values decreased from 3.287 to 3.270 eV, the surface roughness values increased from 58.13 to 60.67 nm, Urbach energy values increased-a 18.3-meV difference in Urbach energy was observed-and in addition, the steepness parameters decreased with increasing Mn content from 0 to 0.75 mol pct

Structural characterizations and optical properties of InSe and InSe: Ag semiconductors grown by Bridgman/Stockbarger technique

Dogan, Seydi/0000-0001-9785-4990; Duman, Songul/0000-0002-3091-3746; GURBULAK, BEKIR/0000-0002-5343-4107WOS: 000342955800018Undoped InSe and Ag doped InSe (InSe:Ag) single crystals have been grown by using the Bridgman/Stockbarger method. the freshly cleaved crystals have mirror-like surfaces even without using mechanical treatment. the structure and lattice parameters of the undoped InSe and InSe:Ag semiconductors have been analyzed using a X-ray diffractometer (XRD), Scanning electron microscopy (SEM) and energy dispersive X-rays (EDX) techniques. It is found that the InSe and InSe:Ag crystals had hexagonal structure, and calculated lattice constants were found to be a=4.002 angstrom and c=17.160 angstrom for InSe and a=4.619 angstrom and c=17.003 angstrom for InSe:Ag. the crystallite sizes have been calculated to be 40-150 nm for InSe and 75-120 nm for InSe:Ag from the SEM results. Ag doping causes a significant increase in the XRD peak intensity. It has been observed from EDX results that InSe contains In=57.12%, Se=38.08% and O=4.81%, respectively. Absorption measurements have been carried out in InSe and InSe:Ag samples in the temperature range 10-320 K with a step of 10 K. the first exciton energies for n=1 were calculated as 1.328, 1.260 eV in InSe and were 1.340, 1.282 eV in InSe:Ag at 10 K and 320 K, respectively. (C) 2014 Elsevier B.V. All rights reserved.Ataturk University Research FundAtaturk University [2012/458, 2012/461, 2013/286, 2013/311]This work was supported by the Ataturk University Research Fund, Project no: 2012/458, 2012/461, 2013/286, 2013/311

Growth and characterization of Ag/n-ZnO/p-Si/Al heterojunction diode by sol-gel spin technique

Duman, Songul/0000-0002-3091-3746; Dogan, Seydi/0000-0001-9785-4990; Turgut, Guven/0000-0002-5724-516X; GURBULAK, BEKIR/0000-0002-5343-4107WOS: 000312149700019Polycrystalline ZnO thin film was obtained on the p-Si for the heterojunction diode fabrication by sol-gel method. X-ray diffraction study showed that the texture of the film is hexagonal with a strong (002) preferred direction. Scanning electron microscope image of ZnO showed that the obtained ZnO thin films had more porous character. High purity vacuum evaporated silver (Ag) and aluminum (Al) metals were used to make Ohmic contacts to the n-ZnO/p-Si heterojunction structure. the electrical properties of Ag/n-ZnO/p-Si/Al diode were investigated by using current-voltage measurements. Ag/n-ZnO/p-Si/Al heterojunction diode showed a rectification behavior, and its ideality factor and barrier height values were found to be 2.03 and 0.71 eV by applying a thermionic emission theory, respectively. the values of series resistance from dV/d (lnI) versus I and H(I) versus I curves were found to be 42.1 and 198.3 Omega, respectively. (C) 2012 Elsevier B.V. All rights reserved.Ataturk University Research FundAtaturk University [2011/98]This work was supported by the Ataturk University Research Fund, Project no 2011/98. One of the authors (E.F. Keskenler) would like to thank to Mustafa Furkan Keskenler for technical support

The Advent of Indium Selenide: Synthesis, Electronic Properties, Ambient Stability and Applications

Among the various two-dimensional semiconductors, indium selenide has recently triggered the interest of scientific community, due to its band gap matching the visible region of the electromagnetic spectrum, with subsequent potential applications in optoelectronics and especially in photodetection. In this feature article, we discuss the main issues in the synthesis, the ambient stability and the application capabilities of this novel class of two-dimensional semiconductors, by evidencing open challenges and pitfalls. In particular, we evidence how the growth of single crystals with reduced amount of Se vacancies is crucial in the road map for the exploitation of indium selenide in technology through ambient-stable nanodevices with outstanding values of both mobility of charge carriers and ON/OFF ratio. The surface chemical reactivity of the InSe surface, as well as applications in the fields of broadband photodetection, flexible electronics and solar energy conversion are also discussed

Fabrication and characterization of Al/Cu2ZnSnS4/n-Si/Al heterojunction photodiodes

Turgut, Guven/0000-0002-5724-516X; Dogan, Seydi/0000-0001-9785-4990; Duman, Songul/0000-0002-3091-3746; GURBULAK, BEKIR/0000-0002-5343-4107WOS: 000333194100009Cu2ZnSnS4 (CZTS) thin film has been synthesized by a sol-gel spin-coating technique on the n-Si substrate to fabricate heterojunction photodiodes. An X-ray diffraction study has shown that the film is polycrystalline with a strong (224) preferred orientation of CZTS and there are also multiphase structures. Atomic force microscopy studies have revealed that spherical nanoparticles have homogenously scattered on the surface of the film and the surface roughness has been found to be 4.65nm. the optical bandgap value has been found to be 1.54eV, which is very suitable for photovoltaic and optoelectronic applications. the electrical properties of Al/CZTS/n-Si/Al diode have been investigated by using current-voltage measurements. the Al/CZTS/n-Si/Al heterojunction photodiode has shown a rectification behavior, and its ideality factor and barrier height values have been found to be 2.69 and 0.70eV, respectively. the values of series resistance from dV/d(lnI) versus I and H(I) versus I curves have been calculated to be 4.3 and 4.7k, respectively. It has been seen that there is a good agreement between the two values. the obtained results indicate that the Al/n-Si/Cu2ZnSnS4/Al diode can be used as a photodiode in optoelectronic applications, especially for solar energy conversion.Ataturk University Research FundAtaturk University [2012/282, 2012/283, 2013/154]This work was supported by the Ataturk University Research Fund, Projects nos. 2012/282, 2012/283, and 2013/154. One of the authors (G. Turgut) would like to thank Prof. Dr. Umit Turgut and Assoc. Prof. Refik Dilber for technical support

Improving the Efficiency of Gallium Telluride for Photocatalysis, Electrocatalysis, and Chemical Sensing through Defects Engineering and Interfacing with its Native Oxide

Gallium telluride (GaTe) is a van der Waals semiconductor, currently adopted for photonic and optoelectronic devices. However, the rapid degradation of GaTe in air, promoted by Te vacancies, is detrimental for device applications. Here, it is demonstrate that the surface oxidation of GaTe can be unexpectedly exploited for expanding the breadth of applications of GaTe. Specifically, the formation of a nanoscale sub-stoichiometric wide-band-gap Ga2O3 skin, promoted by Te vacancies, over narrow-band-gap GaTex upon air exposure is beneficial for electrocatalysis, photocatalysis, and gas sensing . In particular, the Heyrovsky step (H-ads + H+ + e(-) -&gt; H-2) of hydrogen evolution reaction in an acidic medium is barrier-free for the sub-stoichiometric gallium-oxide/gallium-telluride heterostructure, which also enables a significant reduction of costs with respect to state-of-the-art Pt/C electrodes. In the photocatalytic process, the photo-generated electrons migrate from GaTe to Ga2Ox skin, which acts as the chemically active side of the interface. Moreover, the Ga2O3/GaTe heterostructure is a suitable platform for sensing of H2O, NH3, and NO2 at operational temperatures extended up to 600 degrees C (useful for gas detection in combustion processes), mainly due to the increased area of charge redistribution after adsorption achieved upon oxidation of GaTe