Browsing by Author "Karatay, A."

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Citation - WoS: 8
Citation - Scopus: 7
Structural and Optical Characteristics of Thermally Evaporated Tlgase₂ Thin Films
(Elsevier, 2022) Isik, M.; Işık, Mehmet; Karatay, A.; Gasanly, N. M.; Işık, Mehmet; Department of Electrical & Electronics Engineering; Department of Electrical & Electronics Engineering
The present paper reports the structural and optical properties of thermally evaporated TlGaSe2 thin films. X-ray diffraction pattern of evaporated film presented two diffraction peaks around 24.15 and 36.00 degrees which are associated with planes of monoclinic unit cell. Surface morphology of the TlGaSe2 thin films was investigated by scanning electron and atomic force microscopy techniques. Although there was observed some ignorable amount of clusters of quasi-spherical shape in the scanning electron microscope image, the film surface was observed almost uniform. Raman spectrum exhibited six peaks around 253, 356, 488, 800, 1053 and 1440 cm(-1) associated with possible vibrational mode combinations. Band gap energy of the thin film was determined as 3.01 eV from the analyses of transmission spectrum. Transmission spectrum presented strong Urbach tail and analyses of corresponding region resulted in Urbach energy of 0.66 eV. The structural and optical properties of deposited TlGaSe2 thin films were compared with those of single crystal. This comparison would provide valuable information about influence of thickness on the studied compounds.
Citation - WoS: 7
Citation - Scopus: 8
Study of the Structural and Optical Properties of Thallium Gallium Disulfide (tlgas₂) Thin Films Grown Via Thermal Evaporation
(Iop Publishing Ltd, 2022) Isik, M.; Karatay, A.; Ech-Chergui, A. N.; Gasanly, N. M.
Thallium gallium disulfide (TlGaS2) belonging to layered structured semiconducting family has been a significant compound due to its outstanding characteristics. Its layered characteristics take attention for two-dimensional (2D) material research area and thus TlGaS2 is known as promising layered compound to develop 2D materials for optoelectronic devices. To the best of our knowledge, the present work is the first one investigating TlGaS2 thin films grown by thermal evaporation method. The current study focused into the structural, morphological, and optical characteristics of thermally evaporated TlGaS2 thin films. X-ray diffraction pattern of the films exhibited one peak around 36.10 degrees which was associated with (-422) plane of the monoclinic crystalline structure. The atomic compositional ratio of Tl:Ga:S was found to be suitable for the chemical formula of TlGaS2. Scanning electron microscopy images showed uniformly and narrowly deposited nanoparticles with sizes varying between 100 and 200 nm. Room temperature transmission measurements were recorded to obtain the bandgap energy of the evaporated thin films. Tauc analyses indicated direct band gap energy of 2.60 eV. Finally, Urbach energy was obtained as 95 meV. The results of the present paper would provide valuable insight to 2D material technology to understand the potential device applications of the TlGaS2.