Person: AHMETOĞLU, MUHİTDİN
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AHMETOĞLU
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MUHİTDİN
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Publication A new prospect to measure the built-in potential for photodiodes(Elsevier, 2023-12-01) Hacıismailoğlu, M. Cüneyt; Ahmetoğlu, Muhitdin; HACIİSMAİLOĞLU, MUHAMMED CÜNEYT; AHMETOĞLU, MUHİTDİN; Fen Edebiyat Fakültesi; Fizik Bölümü; 0000-0002-0781-3376; KDM-6805-2024; K-7950-2012We present a novel approach to determine the built-in potential for photodiodes, which depends on the excitation of the photodiode by a pulsed or modulated light under forward bias. The proposed method was tested for commercially available photodiodes and the measurement results were compared with the values, which were obtained by conventional current-voltage and capacitance-voltage measurements. It was found that the proposed method gave consistent results with current-voltage and capacitance-voltage measurements. For the confirmation of the accuracy of this method, temperature dependent measurements were also performed for Si photodiode in a temperature range of 298 - 333 K to compare the obtained built-in potential values with theory. This analysis showed that the results of the proposed method were more reliable than the conventional measurements.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; Fen Edebiyat Fakültesi; Fizik Bölümü; 0000-0002-9555-6903; KDM-6805-2024Photodiodes 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.Publication A novel self-powered filterless narrow-band near-infrared photodiode of Cu₂S/Si p+-p isotype heterojunction device with very low visible light noise(Elsevier, 2022-07-08) Kaplan, Hüseyin Kaan; Akay, Sertan Kemal; Ahmetoğlu, Muhitdin; AKAY, SERTAN KEMAL; AHMETOĞLU, MUHİTDİN; KAPLAN, HÜSEYİN KAAN; Fen Edebiyat Fakültesi; Fizik Bölümü; GWV-7916-2022; R-7260-2016; KDM-6805-2024This study aims to achieve a filterless, narrow-band, near-infrared photodiode based on a p(+)-Cu2S/p-Si isotype heterojunction device. The device is developed by depositing 60 nm thick Cu2S thin film on Si substrates from Copper Sulfide pieces via the Thermionic Vacuum Arc technique (TVA). The molecular structure of the thin film is analyzed by utilizing Raman and X-Ray photoelectron spectroscopy (XPS) and confirmed to be in the Cu2S phase. Moreover, the high hole concentration in Cu2S is correlated with XPS results. The photodiode exhibits a response climax centered at 1049 nm and a full-width at half-maximum (FWHM) value of 10(4 )nm. An outstanding responsivity value of 375 mA/W (at 0 V bias) is obtained at a peak wavelength of 1049 nm, which surpasses most filterless, narrow-band photodiodes. Furthermore, while operating at 0 V bias, the photodiode showed an excellent specific detectivity value of 4.17 x 10(11) Jones with a 1.7 x 10(3) on/off ratio (at 1049 nm, 11.47 mW/cm(2)), in addition to its high photocurrent stability and response speed (under 0.8 s). In light of these findings, this proof-of-concept device is a great candidate as a filterless, narrow-band, NIR self-powered photodiode.Publication Electrical and optical properties of photodiode structures formed by surface polymerization of [p (egdma-vpca)-swcnt] films on n-gaas(Elsevier Science Bv, 2019-09-15) Kirezli, Burcu; Ahmetoglu (Afrailov), Muhitdin; AHMETOĞLU, MUHİTDİN; Kara, Ali; KARA, ALİ; Fen Edebiyat Fakültesi; Fizik Bölümü; 0000-0003-2457-6314; AAG-6271-2019; KDM-6805-2024Poly (ethylene glycol dimethacrylate-1-vinyl-1H-pyrrole-2-carboxylic acid)/carbon nanotube, single-walled)/n-GaAs ([P (EGDMA-VPCA)-SWCNT]/n-GaAs) photodiode structures were fabricated by using surface polymerization method. Electrical and optical properties were measured at several temperatures. Dark and light current characteristics were investigated. Spectral photoresponse measurements of the structure were made at room temperature. The maximum open circuit voltage (Voc) and short-circuit current (Isc) values for the diode under 20 mW/cm(2) were obtained to be 0.52 V and 54.63 mu A respectively. That showed that the fabricated structure exhibited rectification behavior that makes it a good candidate for optoelectronic device applications.Publication Electrical and optical characteristics of n-GaSb/n-Gain 0.24 AsSb/p-GaAl 0.34 AsSb heterostructure photodiode(Polish Acad Sciences Inst Physics, 2015-04-01) Ahmetoğlu, Muhittin; Küçür, Banu; Andreev, I. A.; Kunitsyna, E. V.; Mikhailova, M. P.; Yakovlev, Y. P.; AHMETOĞLU, MUHİTDİN; Küçür, Banu; Fen Edebiyat Fakültesi; Fizik Bölümü; CZA-5782-2022; KDM-6805-2024In the present paper, electrical and optical properties of n-GaSb/n-GaIn0.24AsSb/p-GaAl0.34AsSb double heterostructure (DH) with a diameter of 0.3 mm are reported. The current-voltage (I-V) characteristics of the structure were investigated at several temperatures in both, dark and under the illumination conditions. The effect of illumination was studied at different intensity values. Short circuit current and open circuit voltage as a function of intensity of incident light in photovoltaic mode are investigated.Publication N+-GaSb/n o -GainAsSb/P +-GaSb type II heterojunction photodiodes with low radiation damage(Natl Inst Optoelectronics, 2018-09-01) Ahmetoglu (Afrailov), Muhittin; Kirezli, Burcu; Kaynak, Gökay; Andreev, I. A.; Kunitsyna, E., V; Mikhailova, M. P.; Yakovlev, Yu P.; AHMETOĞLU, MUHİTDİN; Kirezli, Burcu; Kaynak, Gökay; Fen Edebiyat Fakültesi; Fizik Bölümü; 0000-0002-9555-6903; KDM-6805-2024; FEP-7816-2022; CYZ-0032-2022The electrical characteristics of a double type II heterojunction in the GaSb/GalnAsSb/GaSb system with staggered band alignmentwere studied. The dark current mechanisms in the heterostructures were investigated at several temperatures. The experimental results shows that, the low temperature region the tunneling mechanism of the current flow dominates in both, forward and reverse biases. Have been investigated the radiation effect of Co-60 (gamma)-ray source with 6 MeV photon energy and 1.5x10(11) gamma/cm(2) fluency on the electrical and optical characteristics.Publication Photocurrent amplification in a isotype N+-GaSb/n⁰-GaInAsSb type II heterojunctions(Elsevier, 2008-10-01) Ahmetoğlu (Afrailov), Muhitdin; AHMETOĞLU, MUHİTDİN; Fen Edebiyat Fakültesi; Fizik Bölümü; KDM-6805-2024The effect of photocurrent amplification was observed in the type II isotype staggered-lineup N+-GaSb/n(0)-GaInAsSb single heterostructure. The illumination intensity influence to the gigantic photocurrent gain effect for applied bias voltage have been studied for this structures. A mechanism of photocurrent amplification in isotype GaSb/GaInAsSb structure due to hole confinement at the type II interface is observed, its magnitude being bias voltage and light intensity dependent. It is shown that the exponential dependence of the photocurrent on intensity confirm the photocurrent gain at small bias is due to modulation of a barrier transparency by the non-equilibrium holes trapped in the potential well in the type II interface as a previously predicted theoretically. (C) 2008 Elsevier B.V. All rights reserved.