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Article Citation - WoS: 39Citation - Scopus: 39Illumination and Voltage Effects on the Forward and Reverse Bias Current-Voltage (i-V) Characteristics in In/In2< Photodiodes(Springer, 2021) Yukselturk, Esra; Surucu, Ozge; Terlemezoglu, Makbule; Parlak, Mehmet; Altindal, SemsettinThe illumination and voltage effects on the I-V measurements of the fabricated In/In2S3/p-Si photodiode were investigated in dark and under various illumination intensities (20-100 mW/cm(2)) between +/- 2 V. Two linear regions in the forward-bias ln(I)-V plots were observed. The value of diode ideality factor (n) had an increasing trend with increasing illumination intensity while the barrier height (phi(Bo)) had a decreasing trend due to the increase of photocurrent. The photodiode properties were also investigated, and the value of linear-dynamic value range (LDR) was found to be 20.56 dB. The photoresponse (I-ph/I-dark), the photoresponsivity (R), and specific detectivity (D*) of the photodiode were calculated as a function of the illumination. The open-circuit voltage (V-oc) and short-current (I-sc) were found to be 0.36 V and 2.87 mA under 100 mW.cm(-2) illumination intensity, respectively. The possible conduction mechanisms (CMs) were investigated using the forward ln(I)-V and reverse ln(I)-V-0.5 plots. The energy-dependent surface states (N-ss) profile was extracted from the positive I-V data by considering voltage-dependent barrier height (BH) and ideality factor (n) in dark and illumination at 100 mW/cm(2).Article 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, SerhatGeneralized 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.Article Citation - WoS: 1Citation - Scopus: 1Nanowire Geometry Effects on Devices and Transport Mechanisms: Sns2 Heterojunction(Springer, 2023) Coskun, Emre; Emir, Cansu; Terlemezoglu, Makbule; Parlak, MehmetThe 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.
