Browsing by Author "Ahmetoglu, Muhitdin"

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    The determination of series resistance and interface state density distributions of Au/p-type GaAs Schottky barrier diodes
    (Natl Inst Optoelectronics, 2013) Özer, Metin; Güzel, Tamer; Asimov, A.; Ahmetoglu, Muhitdin; Kucur, Banu; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Fizik Anabilim Dalı.; 55849632800; 55849025200; 36903670200
    The electronic and interface state density distribution properties obtained from current voltage (I-V) and capacitance-voltage (C-V) characteristics of Au/p-type GaAs Schottky barrier diode (SBD) at room temperature was investigated. The (I-V)-T characteristics are analysed on the basis of thermionic emission (TE). The forward bias I-V of SBDs have been studied at room temperature. SBD parameters such as ideality factor n, series resistance (Rs) determined by Cheung's functions and Schottky barrier height, Phi(bo), are investigated as functions of temperature. The diode parameters such as ideality factor, series resistance and barrier heights were found as 1.76-2.16 and 2.2-1.8 Omega and 0.53-0.72 eV, respectively. The diode shows non-ideal I-V behaviour with an ideality factor greater than unity. Furthermore, the energy distribution of interface state density was determined from the forward bias I-V characteristics by taking into account the bias dependence of the effective barrier height. The results show the presence of thin interfacial layer between the metal and semiconductor.
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    Electrical properties of photodiodes based on p-GaSb/p-GaInAsSb/N-GaAlAsSb heterojunctions
    (Maik Nauka/Interperiodica/Springer, 2008-11) Andreev, Igor; Kunitsyna, Ekaterina; Mikhailova, Maya; Yakovlev, Yu. P.; Ahmetoglu, Muhitdin; Kaynak, Gökay; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Fizik Bölümü.; 16021109400; 12042075600
    We have studied the electrical characteristics of photodiodes based on p-GaSb/p-GaInAsSb/N-GaAlAsSb heterojunctions and investigated the mechanisms of current transfer in these heterostructures at various temperatures. A comparison of the theoretical results and experimental data showed that the tunneling charge transfer mechanism dominates at low temperatures (T < 150 K) under both forward and reverse bias conditions. The tunneling current becomes a determining factor at an electric field strength in the p-n junction of no less that 10(5) V/cm, which is related to a small bandgap width of the materials studied and low effective masses of electrons and holes.
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    Publication
    Photodiodes for detecting the emission of quantum-sized disc lasers operating in the whispering gallery modes (2.2-2.3 μm)
    (Pleiades Publishing Inc, 2020-07-01) Kunitsyna, E., V; Royz, M. A.; Andreev, I. A.; Grebenshchikova, E. A.; Pivovarova, A. A.; Lebiadok, Ya, V; Mikulich, R. Yu; Iliinskaya, N. D.; Yakovlev, Yu P.; Ahmetoglu, Muhitdin; AHMETOĞLU, MUHİTDİN; Bursa Uludağ Üniversitesi/Fen Edebiyat Fakültesi/Fizik Bölümü.; 0000-0002-9555-6903; KDM-6805-2024
    Photodiodes based on solid solutions in the GaSb-InAs system are for the first time applied to study the spectral characteristics of single and coupled whispering-gallery-mode (WGM) lasers emitting in a range of 2.2-2.3 mu m. The capacity of photodiodes with a photosensitive area 2.0 mm in diameter isC= 520 pF atU= -2 V, which corresponds to a time constant of tau = 53 ns. It is shown that the parameters of the fabricated photodiodes make it possible to detect the emission of quantum-sized disc lasers at room temperature not using cryogenic cooling.