Browsing by Author "Coskun, Emre"

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Citation Count: 0
Nanowire Geometry Effects on Devices and Transport Mechanisms: Sns₂ Heterojunction
(Springer, 2023) Coskun, Emre; Emir, Cansu; Terlemezoglu, Makbule; Parlak, Mehmet
The semiconductor nanowire technology has become essential in developing more complex and efficient devices. In this study, the Si nanowire (SiNW) heterojunction structure with a two-dimensional SnS2 thin film was investigated. The SiNW array was created by the metal-assisted etching method because of length control and production over large areas of nanowires. The created SiNW has more diminishing reflectivity compared with Si planar substrate. The diode characteristics of SnS2/SiNW and SnS2/Si planar heterojunctions were investigated by dark current analysis at room temperature, and the improving diode characteristics by the three-dimensional interface between SiNW and SnS2 thin film were discussed. Transport mechanisms of the SiNW heterojunction were also studied for various methods. Thermionic emission and thermally assisted tunneling models are the dominant mechanisms for low voltages (0.02-0.20 V), and the space charge limiting current mechanism dominates the current for comparingly high voltages (0.20-0.40 V). All the values reveal the significant impact of the SiNW on heterojunctions for improving efficiency.
Citation Count: 0
A New Method To Determine the Continuous Refractive Index of an Absorbing Film by Generalized Stockwell Transform
(Elsevier Sci Ltd, 2023) Coskun, Emre; Emir, Cansu; Selamet, Semanur; Parlak, Mehmet; Ozder, Serhat
Generalized Stockwell Transform (GST) was adapted to analyze a transmittance signal to continuously determine the refractive index and extinction coefficient. The process is built by analyzing oscillation frequencies of the transmission signal where oscillations exist. The simulation studies clearly show the advantage of the locally referenced phase property of the presented method. The validity of the method was checked for a CdS thin film. The results determined by the GST method are consistent with the results determined by envelope and other signal analyzing methods, and the literature. The noise and relative error analysis of the method was also discussed.
Citation Count: 1
Structural and Optical Properties of Interfacial Inse Thin Film
(Amer Chemical Soc, 2024) Emir, Cansu; Tataroglu, Adem; Coskun, Emre; Ocak, Sema Bilge
This study presents a comprehensive investigation of the optical and structural characteristics of the indium selenide (InSe) film prepared on a glass substrate. The structural characteristics of the InSe film were analyzed using characterization techniques including X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy while the UV-vis spectrophotometry method was used in the spectral range between 500 and 1000 nm to examine the optical characteristics. Thus, the UV-vis spectroscopic data were used to extract several optical parameters including extinction coefficient (k), optical band gap (E-g), refractive index (n), absorption coefficient (alpha), and optical conductivity (sigma(opt)). The optical transition of InSe was found as a direct transition. However, the optical analysis of this study has revealed that the InSe film has the potential to be used in various optoelectronic and photovoltaic applications.