Browsing by Author "Sarigul, N."

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Citation Count: 7
Defect Characterization in Bi₁₂geo_{20< Single Crystals by Thermoluminescence}
(Elsevier, 2021) Delice, S.; Işık, Mehmet; Isik, M.; Sarigul, N.; Gasanly, N. M.; Department of Electrical & Electronics Engineering
Bi12GeO20 single crystal grown by Czochralski method was investigated in terms of thermoluminescence (TL) properties. TL experiments were performed for various heating rates between 1 and 6 K/s in the temperature region of 300-675 K. One TL peak with peak maximum temperature of 557 K was observed in the TL spectrum as constant heating rate of 1 K/s was employed. Curve fitting, initial rise and variable heating rate methods were applied to calculate the activation energy of trap level corresponding to this TL peak. Analyses resulted in a presence of one trap center having mean activation energy of 0.78 eV. Heating rate characteristics of revealed trap center was also explored and theoretically well-known behavior that TL intensity decreases and peak maximum temperature increases with heating rates was observed for the trap level. Distribution of trapping levels was studied by thermally cleaning process for different T-stop between 425 and 525 K. Quasi-continuously distributed trapping levels were revealed with mean activation energies ranging from 0.78 to 1.26 eV. Moreover, absorption analysis revealed an optical transition taking place between a defect level and conduction band with an energy difference of 2.51 eV. These results are in good agreement for the presence of intrinsic defects above valence band in Bi12GeO20 crystals.
Citation Count: 12
Thermoluminescence Characteristics of Bi 12 Sio 20 Single Crystals
(Elsevier, 2020) Isik, M.; Işık, Mehmet; Sarigul, N.; Gasanly, N. M.; Department of Electrical & Electronics Engineering
[No Abstract Available]
Citation Count: 1
Thermoluminescence characteristics of GaSe and Ga₂Se₃single crystals
(Elsevier, 2022) Işık, Mehmet; Sarigul, N.; Gasanly, N. M.; Department of Electrical & Electronics Engineering
GaSe and Ga2Se3 are semiconducting compounds formed from same constituent elements. These compounds have been attractive due to their optoelectronic and photovoltaic applications. Defects take remarkable attention since they affect quality of semiconductor devices. In the present paper, deep defect centers in GaSe and Ga2Se3 single crystals grown by Bridgman method were reported from the analyses of thermoluminescence measurements performed in the 350-675 K range. Experimental TL curves of GaSe and Ga2Se3 single crystals presented one and two overlapped peaks, respectively. The applied curve fitting and initial rise techniques were in good agreement about trap activation energies of 0.83 eV for GaSe, 0.96 and 1.24 eV for Ga2Se3 crystals. Crystalline structural properties of the grown single crystals were also investigated by x-ray diffraction measurements. The peaks observed in XRD patterns of the GaSe and Ga2Se3 crystals were well-consistent with hexagonal and zinc blende structures, respectively.