Browsing by Author "Gökşen, K."

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    Defect luminescence in undoped p-type GaSe
    (Taylor & Francis, 2001) Aydınlı, Atilla; Gasanly, N. M.; Gökşen, K.
    Photoluminescence (PL) spectra of undoped single crystals of the layered semiconductor GaSe have been measured in the temperature range from 10 K to room temperature and in the wavelength range from 635 to 750 nm. Two wide bands centred at 644 and 695 nm have been observed at T = 10 K. A detailed analysis of the spectra obtained by varying the excitation intensity and temperature resulted in the identification of the levels involved. A simple model is proposed to account for the observed data.
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    Low-temperature photoluminescence study of GaS0.5Se0.5 layered crystals
    (Elsevier Science, 2001) Aydnl, A.; Gasanly, N. M.; Gökşen, K.
    Photoluminescence (PL) spectra of GaS0.5Se0.5 layered single crystals have been studied in the wavelength range of 565-860 nm and in the temperature range of 15-170 K. Two PL bands centered at 585 nm (2.120 eV) and 640 nm (1.938 eV) were observed at T = 15 K. Variations of both bands were studied as a function of excitation laser intensity in the range from 10-3 to 15.9 W cm-2. These bands are attributed to recombination of charge carriers through donor-acceptor pairs located in the band gap. Radiative transitions from shallow donor levels located at 0.029 and 0.040 eV below the bottom of the conduction band to deep acceptor levels located 0.185 and 0.356 eV above the top of the valence band are suggested to be responsible for the observed A- and B-bands in the PL spectra, respectively. A simple energy level diagram explaining the recombination process is proposed.