Akademik Veri Yönetim Sistemi
Tezin Türü: Doktora
Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Fen Edebiyat Fakültesi, Fizik Bölümü, Türkiye
Tezin Onay Tarihi: 2016
Öğrenci: SERDAR DELİCE
Danışman: NIZAMI HASANLI
Özet:Thermoluminescence (TL) experiments for ternary and quaternary layered single crystals were carried out in 10−300 K temperature range by employing various heating rates between 0.2 and 1.2 K/s. The TL emissions coming from the trapping centers in the studied samples brought out the TL spectra exhibiting peaks at different temperature regions for each crystals. These peaks were taken under consideration to reveal the TL properties of the associated trap levels. Characterizations of defect centers existing in the crystals were achieved utilizing the best-known analysis methods (curve fitting, initial rise, peak shape and heating rate methods) of TL theory. Thermal activation energies, capture cross sections and frequency factors of trapping levels were calculated with used TL analysis methods. Corrections due to temperature lag effect were taken into account for some of the studied crystals to evaluate the activation energy using heating rate method. Order of kinetics exhibited by trap levels were determined through curve fitting and peak shape methods. TL mechanisms of the trap centers in the crystals were studied in depth by investigating the behaviors against different heating rates and stopping temperatures. Although most of the trap levels in the crystals showed the normal heating rate behavior, the traps in Tl2GaInS4 and GaS crystals exhibited the properties of anomalous heating rate behavior. Also, thermal quenching was observed for the Tl2Ga2S3Se crystal. In addition, except for the Tl4In3GaS8 and GaSe:Mn crystals, which possess the continuous distribution of traps and single trap level, respectively, the quasi-continuous distributions of the trapping levels were exhibited in other studied crystals.