Browsing by Author "Colakoglu, T."

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Citation - WoS: 6
Citation - Scopus: 7
Construction of Self-Assembled Vertical Nanoflakes on Cztsse Thin Films
(Iop Publishing Ltd, 2019) Terlemezoglu, M.; Surucu, O. Bayrakli; Colakoglu, T.; Abak, M. K.; Gullu, H. H.; Ercelebi, C.; Parlak, M.
Cu2ZnSn(S, Se)(4) (CZTSSe) is a promising alternative absorber material to achieve high power conversion efficiencies, besides its property of involving low-cost and earth-abundant elements when compared to Cu(In, Ga) Se-2 (CIGS) and cadmium telluride (CdTe), to be used in solar cell technology. In this study, a novel fabrication technique was developed by utilizing RF sputtering deposition of CZTSSe thin films having a surface decorated with self-assembled nanoflakes. The formation of nanoflakes was investigated by detailed spectroscopic method of analysis in the effect of each stacked layer deposition in an optimized sequence and the size of nanoflakes by an accurate control of sputtering process including film thickness. Moreover, the effects of substrate temperature on the formation of nanoflakes on the film surface were discussed at a fixed deposition route. One of the main advantages arising from the film surface with self-assembled nanoflakes is the efficient light trapping which decreases the surface reflectance. As a result of the detailed production and characterization studies, it was observed that there was a possibility of repeatable and controllable fabrication sequence for the preparation of CZTSSe thin films with self-textured surfaces yielding low surface reflectance.
Citation - WoS: 9
Citation - Scopus: 9
Effects of Si Nanowire on the Device Properties of N-znse/P-si Heterostructure
(Springer, 2019) Coskun, E.; Gullu, H. H.; Colakoglu, T.; Emir, C.; Bozdogan, E.; Parlak, M.
The semiconductor nanowire (NW) technology has raised attention owing to its one-dimensional geometry as a solution for lattice mismatch in the fabricated heterostructures. Although, SiNWs have been investigated for various device technologies, there is no published work on the p-n junction formed by deposition of ZnSe thin film on these NW structures, in which this film layer has significant optical and electrical properties in optoelectronics applications. The aim of this study is determining the device properties of n-ZnSe/SiNW heterojunction and obtaining the enhancement in the device application of the NW structure on Si surface with comparing to planar surface. SiNW was produced by metal assisted etching method as a cost-efficient process, and the ZnSe film was deposited on SiNW and planar Si substrates by thermal evaporation of elemental sources. The optical band gap of the deposited ZnSe film was determined as 2.7eV which is in a good agreement with literature. The ideality factor and series resistance values of the ZnSe/SiNW and ZnSe/Si heterojunctions were calculated as 3.12, 461 , and 4.52, 7.26x103, respectively. As a result of utilizing SiNW structure, a spectacular improvement in terms of the physical parameters related to device properties was achieved.