Browsing by Author "Goksen, K."

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Determination of Trapping Parameters in N-Ga4se3s by Thermally Stimulated Current Measurements
(Taylor & Francis Ltd, 2009) Goksen, K.; Gasanly, N. M.
Thermally stimulated current (TSC) measurements were carried out on as-grown n-Ga4Se3S layered crystals in the temperature range 10-300 K. The experimental data were analysed by using different heating rates, initial rise, curve fitting and isothermal decay methods. The results of the analysis showed good agreement with each other. The measurements revealed the presence of one trapping level with activation energy of 23 meV. The corresponding capture cross-section and concentration of traps were found to be 2.2 10-23 cm2 and 2.9 1011 cm-3, respectively. TSC experiments showed the presence of an exponential distribution of electron-trapping states in Ga4Se3S crystal. The variation of one order of magnitude in the trap density for every 34 meV was obtained.
Trap Distribution in Tlins2 Layered Crystals From Thermally Stimulated Current Measurements
(Korean Physical Soc, 2008) Isik, M.; Goksen, K.; Gasanly, N. M.; Ozkan, H.
We have carried out thermally stimulated current (TSC) measurements with the current flowing along the layer on as-grown TlInS2 layered single crystals in the low temperature range 10 - 110 K with different heating rates of 0.1 - 1.5 K/s. Experimental evidence was found for the presence of two shallow electron trapping centers with activation energies of 12 and 14 meV. Their capture cross sections have been determined as 2.2 x 10(-23) and 7.1 x 10(-25) cm(2), respectively. It was concluded that retrapping in these centers is negligible, which was confirmed by the good agreement between the experimental results and the theoretical predictions of the model that assumed slow retrapping. An exponential distribution of electron traps was revealed from the analysis of the TSC data obtained at different light excitation temperatures. This experimental technique provided a value of 27 meV/decade for the trap distribution. The parameters of the monoclinic unit cell were determined by studying the X-ray powder diffraction.