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Öğe Determination of electrical parameters of ITO/CZTS/CdS/Ag and ITO/CdS/CZTS/Ag heterojunction diodes in dark and illumination conditions(SPRINGER, 2019) Gezgin, Serap Yiğit.; Kiliç, Hamdi Şükür.In this work, ITO/CZTS/CdS/Ag and ITO/CdS/CZTS/Ag heterojunction diodes has been produced, CdS and CZTS thin film layers of the diode have been produced on ITO glass at room temperature using PLD technique. It has been produced CZTS thin films that have a polycrystalline structure that were annealed at the sulfurization temperatures of 325 degrees C, 350 degrees C and 375 degrees C when as-grown CZTS thin film has the amorphous structure. CdS thin films have been grown on substrate at room temperature in 15, 20 and 25 min that have polycrystalline structures. Then, CdS thin film deposited for 20 min was annealed at 200 degrees C temperature and, has better crystal structure compared to other thin films. Diodes have been composed of CZTS thin film annealed in 375 degrees C, CdS thin film was grown during 20 min and, then annealed at 200 degrees C temperature. According to J-V characteristics of diode, diodes exhibit some rectification behaviour in dark and show a photo-electric property under illumination conditions. In this article, the ideality factors of diodes in dark condition have been calculated, their electrical parameters of J(sc), V-oc, FF and eta under the illumination condition have been determined and these electrical properties have been discussed in details.Öğe The electrical characteristics of ITO/CZTS/ZnO/Al and ITO/ZnO/CZTS/Al heterojunction diodes(ELSEVIER GMBH, 2019) Gezgin, Serap Yiğit.; Kılıç, Hamdi Şükür.In this study, ITO/a-CZTS/ZnO1/Al, ITO/ZnO2/a-CZTS/Al and ITO/ZnO2/c-CZTS/Al diode structures were produced by PLD technique and analysed, as well as data are presented. a-CZTS and ZnO thin films were grown as layer by layer thin films on ITO coated glass at room temperature and annealing process was not carried out for these samples. Morphologies and crystal structures of ZnO and a-CZTS thin films were analysed. ZnO thin films have been produced depending on an oxygen ambient gas pressure and a-CZTS thin film has been produced using low laser energies. While ZnO thin films exhibit crystal structure, a-CZTS has amorphous structure. In addition, c-CZTS thin film has also been annealed at 375 degrees C sulfurization temperature at which crystalline structure was obtained. Optical features of thin films were determined by UV-vis spectra and it was observed that a-CZTS and c-CZTS thin films have a high band gap and an ideal band gap, respectively. Diode structure of ITO/a-CZTS/ZnO1/Al has shown normal diode characteristics in dark environment and has different ideality factors for three regions in semi-logarithmic forward bias region. ITO/ZnO2/a-CZTS/Al diode structure has also shown a negative differential resistance and behaved like a tunnelling diode in dark environment exhibiting photoelectric effect under illuminated environment. Short circuit current density is very low, fill factor and open circuit voltage are quite high. In addition, ITO/ZnO2/c-CZTS/Al diode structure has shown some photo-electricity property under illumination conditions. The diode's short circuit current density was found to be higher and open circuit voltage was very low. Electrical characteristics of diodes have been described in some details in this work.Öğe Investigation of conversion efficiency of n-ZnO/p-Si heterojunction device produced by pulsed laser deposition (PLD)(ELSEVIER, 2019) Gezgin, Serap Yiğit.; Kepceoğlu, Abdullah.; Toprak, Ahmet.; Kılıç, Hamdi Şükür.In this study, n-ZnO/p-Si heterojunction was produced by growing polycrystalline Zinc Oxide (ZnO) thin films on p-type Si (100) substrate at 500 mu m thickness using Pulsed Laser Deposition (PLD) method. The crystalline and morphologic structure of ZnO thin film were analysed by X-ray diffraction (XRD) and Atomic Force Microscopy (AFM) techniques. The photovoltaic (PV) property of n-ZnO/p-Si heterojunction was investigated by using current-voltage (J-V) measurement under illumination at 70 mW/cm(2). The silver (Ag) metal thin film was deposited by PLD to make ohmic contacts to the n-ZnO/p-Si heterojunction structure. The barrier height and the ideality factor were calculated to be 0.51 eV and 12.37, respectively, at room temperature (RT). The largest values of open circuit voltage (V-oc) and short circuit current density (J(sc)) were about 250 mV and 1.63 mA/cm(2), respectively. The photoelectric conversion efficiency in the range of 0.12% have been achieved and presented in this paper. (C) 2019 Elsevier Ltd. All rights reserved.Öğe Production and photovoltaic characterisation of n-Si/p-CZTS heterojunction solar cells based on a CZTS ultrathin active layers(ELSEVIER GMBH, 2019) Gezgin, Serap Yiğit.; Houimi, Amina.; Kılıç, Hamdi Şükür.In this study, Au/n-Si/p-CZTS/Ag solar cells have been produced by using PLD technique. Ultrathin CZTS films have been grown on n-Si wafer in different thicknesses depending on number of laser pulses. These ultrathin CZTS films were analysed by XRD, AFM and UV-vis spectra. J-V characteristics of Au/n-Si/p-CZTS/Ag solar cells have been determined based on thickness of ultrathin CZTS films under AM 1.5 solar radiation of 80 mW/cm(2). Short circuit current density (mA/cm(2)), fill factor, open circuit voltage (V) and power conversion efficiency (%) of ultrathin CZTS film solar cells have been determined for device produced in this work. The photovoltaic (PV) characteristics of ultrathin CZTS film solar cells has been discussed in detail in this present article and, as a result, the ideal ultrathin CZTS film solar cell structure having the highest efficiency has been determined and concluded.
