Yazar "Ergün, Yüksel" için Makale Koleksiyonu listeleme
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Barrier lowering effect and dark current characteristics in asymmetric GaAs/AlGaAs multi quantum well structure
Altın, E.; Hoştut, Mustafa; Ergün, Yüksel (Springer, 2011)In this study, we investigate dark current voltage characteristics of GaAs/AlGaAs staircase-like asymmetric multiquantum well structure at various temperatures experimentally. The activation energy is calculated by using ... -
Broadband staircase quantum well infrared photodetector with low dark current
Ergün, Yüksel; Hoştut, Mustafa; Eker, Süleyman Umut; Sökmen, İsmail (Elsevier Science BV, 2006)We present a theoretical investigation of a novel staircase-like quantum well infrared photodetector (QWIP). It detects wavelengths between 8.8 mu m and 12.3 mu m at an applied electric field of F= 6 x 10(4) V/cm at room ... -
Comprehensive growth and characterization study on highly n-doped InGaAs as a contact layer for quantum cascade laser applications
Demir, İlkay; Altuntaş, İsmail; Bulut, Barış; Ezzedini, Maher; Ergün, Yüksel; ElagÖz, Sezai (IOP Publishing LTD, 2018)We present growth and characterization studies of highly n-doped InGaAs epilayers on InP substrate by metal organic vapor phase epitaxy to use as an n-contact layer in quantum cascade laser applications. We have introduced ... -
Dark current and optical properties in asymmetric GaAs/AlGaAs staircase-like multiquantum well structure
Altın, E.; Hoştut, Mustafa; Ergün, Yüksel (Elsevier Science BV, 2013)In this study, we investigate dark current voltage characteristics of GaAs/AlGaAs staircase-like asymmetric multiquantum well structure at various temperatures experimentally. Measured dark current density voltage (J(d)-V) ... -
Effect of exchange-correlation potential on the plasmon dispersions in a doped symmetrical double quantum well
Tüzemen, E. Senadim; Türkoğlu, A.; Ergün, Yüksel; Sökmen, İsmail; Tanatar, B. (Wiley-V C H Verlag GMBH, 2007)We have calculated the plasmon dispersion relations in a doped double quantum well with and without exchange-correlation potential added to the effective potential of the system. The calculations were done for high and low ... -
Electrical and optical performances with extracted minority carrier lifetimes of InAs/GaSb SL photodetector operating in the mid wavelength infrared range
Tansel, Tunay; Hoştut, Mustafa; Ergün, Yüksel (Academic Press LTD- Elsevier Science LTD, 2017)We report a study on the temperature dependence of electrical and optical performance of InAs/GaSb based type-II superlattice (T2SL) pin photodetectors in the mid wavelength infrared range (MWIR). The SL structure exhibits ... -
Exciton states in a quantum dot with parabolic confinement
In this study the electronic eigenstructure of an exciton in a parabolic quantum dot (QD) has been calculated with a high accuracy by using Finite element method (FEM). We have converted the coordinates of electronlight-hole ... -
Ground state energy of excitons in quantum dot treated variationally via Hylleraas-like wavefunction
Şakiroğlu, S.; Doğan, Ue.; Yıldız, Aylin; Akgüngor, K.; Epik, H.; Ergün, Yüksel; Sökmen, I. (IOP Publishing LTD, 2009)In this work, the effects of quantum confinement on the ground state energy of a correlated electron-hole pair in a spherical and in a disc-like quantum dot have been investigated as a function of quantum dot size. Under ... -
Intersubband electron transition across a staircase potential containing quantum wells: light emission
Ergün, Yüksel; Hoştut, Mustafa; Eker, Süleyman Umut; Sökmen, İsmail (Academic Press LTD Elsevier Science LTD, 2005)We present a theoretical investigation of a novel staircase-like light emitter based on the GaAs/GaxAl1-xAs material system. The emission wavelength is around 12 mum. The device operation is based on the intersubband ... -
N structure for type-II superlattice photodetectors
Salihoğlu, Ömer; Muti, Abdullah; Kutluer, Kutlu; Tansel, Tunay; Turan, Raşit; Ergün, Yüksel; Aydınlı, Atilla (Amer Inst Physics, 2012)In the quest to raise the operating temperature and improve the detectivity of type II superlattice (T2SL) photodetectors, we introduce a design approach that we call the "N structure." N structure aims to improve absorption ... -
N-structure based on InAs/AlSb/GaSb superlattice photodetectors
Hoştut, M.; Alyörük, M.; Tansel, Tunay; Kılıç, A.; Turan, Raşit; Aydınlı, A.; Ergün, Yüksel (Academic Press LTD- Elsevier Science LTD, 2015)We have studied the theoretical and experimental properties of InAs/AlSb/GaSb based type-II superlattice (T2SL) pin photodetector called N-structure. Electronic properties of the superlattice such as HH-LH splitting energies ... -
A new approach to quantum well infrared photodetectors: Staircase-like quantum well and barriers
Eker, Süleyman Umut; Hoştut, Mustafa; Ergün, Yüksel; Sökmen, İsmail (Elsevier Science BV, 2006)We present a theoretical investigation of a novel staircase-like quantum well infrared photodetector (QWIP). The proposed structure makes use of quantum wells and barriers with increasing Al content both in the wells and ... -
A study of photomodulated reflectance on staircase-like, n-doped GaAs/Al (x) Ga1-x As quantum well structures
Dönmez, Ömer; Nutku, Ferhat; Erol, Ayşe; Arıkan, Çetin M.; Ergün, Yüksel (Springer, 2012)In this study, photomodulated reflectance (PR) technique was employed on two different quantum well infrared photodetector (QWIP) structures, which consist of n-doped GaAs quantum wells (QWs) between undoped Al (x) Ga1-x ... -
Three-color broadband asymmetric quantum well infrared photodetectors in long wavelength infrared range (LWIR)
Hoştut, Mustafa; Alyörük, M.; Ergün, Yüksel; Sökmen, İsmail (Springer, 2010)A theoretical investigation of a GaAs/AlGaAs-material-system-based four quantum well infrared detector structures consisting of ten periods of three asymmetric quantum well units are presented. Each quantum well in the ... -
Tunable long-wavelength broad band asymmetric quantum well infrared photodetector
Hoştut, Mustafa; Kartal, D.; Ergün, Yüksel; Sökmen, İsmail (IOP Publishing LTD, 2007)We present a theoretical investigation of a GaAs/AlGaAs infrared detector consisting of three asymmetric quantum wells. Each well is designed to yield absorption and a photoresponse at peak wavelengths of 8.2 mu m, 9.5 mu ... -
The variation of electronic properties with the doping concentration of modulation-doped AlxGa1-xAs-GaAs double quantum wells
Ungan, Fatih; Öztürk, Emine; Ergün, Yüksel; Sökmen, İsmail (Academic Press LTD Elsevier Science LTD, 2007)In this paper we have calculated the sub-band structure and the confinement potential of modulation-doped Ga1-xAlxAs-GaAs double quantum wells as a function of the doping concentration. The electronic properties of this ... -
Variational Computations for Excitons in Quantum Dots: a Quantum Monte Carlo Study
Yıldız, A.; Şakiroğlu, S.; Doğan, U.; Akgüngor, K.; Epik, H.; Sökmen, I.; Ergün, Yüksel (World Scientific Publ Co Pte LTD, 2011)A study of variational wave functions for calculation of the ground-state energies of excitons confined in a two-dimensional (2D) disc-like and three-dimensional (3D) spherical parabolic GaAs quantum dots (QDs) is presented. ... -
Voltage Tunable Dual-Band Quantum-Well Infrared Photodetector for Third-Generation Thermal Imaging
Hoştut, M.; Kılıç, Abidin; Şakiroğlu, S.; Ergün, Yüksel; Sökmen, I. (IEEE-Inst Electrical Electronics Engineers Inc, 2011)We investigate the theoretical calculations of the voltage tunable dual-band quantum-well infrared photodetector (QWIP) in the long and very long wavelength infrared range (LWIR and VLWIR). The detector consists of two ...