Browsing by Author "Akcay, Neslihan"

Now showing 1 - 3 of 3

Cu2znsns4 Films Prepared By A Hybrid Pvd Deposition System: A Multi-Layered Graphitic Carbon Intermediate Layer At The Mo/Czts Interface
(JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS, 2024-11) Akcay, Neslihan; Yildirim, Ali Riza; Kesik, Deha; Gremenok, Valery F.; Ozcelik, Suleyman; Ceylan, Abdullah
We report the insertion of a new intermediate layer, a multi-layered graphitic carbon (MLGC), at Mo/CZTS interface and its impact on the structural and morphological characteristics of the back interface and absorber. MLGC was synthesized directly on Mo-coated SLG under a gas mixture flow of H2/CH4 at 550 degrees C via PECVD for 3 and 5 h. CZTS precursors were prepared on SLG/Mo and MLGC-coated SLG/Mo in a hybrid physical vapor deposition system, including evaporation and sputtering techniques, then subjected to sulfurization at 550 degrees C. The sheet resistance of back contact, microstructural parameters of the absorbers, the distributions of C and constituent elements were investigated. The diffraction peaks of the hexagonal Mo2C indicated the reaction between the C and Mo before the MLGC's growth. Raman analysis confirmed the formation of the MLGC during the long deposition time after the Mo2C formation. With the addition of MLGC, the sheet resistance of the back contact decreased from 2 to 0.5 ohm/sq, and the crystallite size of the absorbers improved. Raman spectra from the interface exhibited that MoS2 peaks' intensities significantly reduced with increasing the growth time. This implied that the 5 h-deposited MLGC was more effective in blocking the reaction between Mo and S. The absorbers with the MLGC had more uniform surface morphologies, densely packed grains, and fewer secondary phases. FIB analysis revealed the separation of the absorber with the 5 h-deposited MLGC into two parts due to C impurity. More C diffusion into the absorber for this sample was confirmed by SIMS.
Effect of Post-thermal Annealing on the Structural, Morphological, and Optical Properties of RF-sputtered In2S3 Thin Films
(2023) Akcay, Neslihan; Erenler, Berkcan; Ozen, Yunus; Gremenok, Valery Feliksovich; Buskis, Konstantin Pavlovich; Ozcelik, Suleyman; 0000-0002-3101-7644
Indium sulfide films were deposited by radio frequency magnetron sputtering technique on soda lime glass substrate. The deposition was conducted at the temperature of 150 degrees C and prepared films were then thermally annealed under argon atmosphere at 350 degrees C and 450 degrees C for 30 min. The impact of post-thermal annealing treatment on the properties of the films was investigated. From X-ray diffraction analysis, the formation of the stable tetragonal beta-In2S3 crystal structure was substantiated and revealed that the thermal annealing treatment at 450 degrees C improved the crystallization of the films. The change in surface topographies and morphologies of the films depending on the post-thermal annealing process were examined by atomic force microscopy and scanning electron microscopy techniques, respectively. The stoichiometric ratio of constituent elements in the films was obtained by elemental analysis and it was seen that the films had slightly sulfur (S) deficit composition. It was found that the concentration of S slightly increased with the thermal annealing process. The room temperature photoluminescence spectra revealed that the films included vacancies of sulfur (VS: donor) and indium (In) (VIn: acceptor), indium interstitial (Ini: donor) and oxygen (O) in vacancy of sulfur (OVs: acceptor) defects with strong and broad emission bands at around 1.70, 2.20, and 2.71 eV.
Investigation on the properties ofCu(2)ZnSnSe(4)andCu(2)ZnSn(S,Se)(4)absorber films prepared by magnetron sputtering technique usingZnandZnStargets in precursor stac
(2020) Akcay, Neslihan; Gremenok, Valery Feliksovich; Zaretskaya, Ellen Petrovna; Ozcelik, Suleyman; ABB-7017-2020
Cu(2)ZnSnSe(4)and Cu2ZnSn(S,Se)(4)absorber films were grown on soda lime glass and Mo-coated soda lime glass substrates by deposition of the precursor films via RF magnetron sputtering method in the stacking orders of Cu/Sn/Zn/Mo/SLG and Cu/Sn/ZnS/Mo/SLG using metallic Zn or binary sulfide ZnS targets and subsequently carrying out of selenization process. It was aimed to find out the effect of Zn or ZnS target types and the small amount of S originated from ZnS target material used in the deposition of precursor films on the structural, morphological, optical, and electrical characteristics of the films to be selenized. XRD and Raman spectroscopy analysis showed that the kesterite CZTSe structure was predominantly formed in both cases where Zn and ZnS targets were used. According to the EDX analysis, S content in the prepared film using ZnS target was only around 1.79 at%. This indicated that a considerable amount of S in the film was driven out during the selenization process. Scanning electron microscopy analysis revealed that ZnS target material contributed to the achievement of the absorber films with larger grain size. It was also determined that the thickness of the interfacial MoSe(2)film between the absorber and Mo films decreased by using ZnS target in the precursor film. This was attributed to ZnS layer with a high melting point acting as a barrier layer over Mo film and retarding the diffusion of Se into the Mo film during the selenization process. In addition, the band gap energy values of the Cu(2)ZnSnSe(4)and Cu2ZnSn(S,Se)(4)films were found to be 1.18 and 1.28 eV, respectively.