Browsing by Author "Ozcelik, Fikriye Seyma"

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The Effect of Sn Doping Urbach Tail and Optical Absorption Measurements of InSe Crystal
(Iop Publishing Ltd, 2016) Duman, Songul; Gurbulak, Bekir; Dogan, Seydi; Ozcelik, Fikriye Seyma
InSe and n-InSe:Sn crystals grown by Bridgman-Stockbarger method. Absorption measurements have been carried out in InSe and InSe:Sn samples in the temperature range 10-320 K with a step of 10 K. Sn doping to InSe have increased the absorption intensity and caused both increasing in the Urbach energy, decreasing in the steepness parameters and shifting of the absorption edge towards the shorter wavelengths. The steepness parameters and Urbach energy values for InSe and InSe:Sn samples have also increased with increasing sample temperature in the range 10-320 K.
An Evaluation of Structural, Topographic, Optical, and Temperature-Dependent Electrical Features of Sol-Gel Spin-Coated P-NiO/N-Si Heterojunction
(Springer, 2017) Turgut, Guven; Duman, Songul; Ozcelik, Fikriye Seyma
p-NiO/n-Si heterodiode was deposited with an easy and cheap sol-gel route using a spin coater. The XRD results revealed that NiO film had polycrystalline cubic bunsenite structure with (200) preferential direction. The AFM and SEM micrographs indicated that the film was composed of homogenously distributed nanoparticles on n-Si surface. The uniform scattering of Ni and O elements was also seen from EDX mapping pictures. The band gap value for NiO sample was found to be 3.74 eV. The current-voltage (I-V) properties of Ag/p-NiO/n-Si heterojunction were inquired in the temperature range of 80 K to 300 K (-193 A degrees C to 27 A degrees C). The temperature coefficient of barrier height of the Ag/p-NiO/n-Si heterojunction was determined to be 2.6 meV/K. The I-V measurements showed that the barrier height of the heterojunction increased with an increment in the temperature.