Browsing by Subject "Resonant cavity"
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Item Open Access Design and optimization of high-speed resonant cavity enhanced Schottky photodiodes(Institute of Electrical and Electronics Engineers, 1999-02) Gökkavas, M.; Onat, B. M.; Özbay, Ekmel; Ata, E. P.; Xu, J.; Towe, E.; Ünlü, M. S.Resonant cavity enhanced (RCE) photodiodes (PD's) are promising candidates for applications in optical communications and interconnects where high-speed high-efficiency photodetection is desirable. In RCE structures, the electrical properties of the photodetector remain mostly unchanged; however, the presence of the microcavity causes wavelength selectivity accompanied by a drastic increase of the optical field at the resonant wavelengths. The enhanced optical field allows to maintain a high efficiency for faster transit-time limited PD's with thinner absorption regions. The combination of an RCE detection scheme with Schottky PD's allows for the fabrication of high-performance photodetectors with relatively simple material structures and fabrication processes. In top-illuminated RCE Schottky PD's, a semitransparent Schottky contact can also serve as the top reflector of the resonant cavity. We present theoretical and experimental results on spectral and high-speed properties of GaAs-AlAs-InGaAs RCE Schottky PD's designed for 900-nm wavelength.Item Open Access Design, fabrication and characterization of high performance resonant cavity enhanced photodetectors(Bilkent University, 1998) Bıyıklı, NecmiPhotodetectors are essential components of optoelectronic integrated circuits and fiber optic communication systems. For higher system performances, photoreceivers with high bandwidth-efficiency products are needed. A new family of photodetectors introduced in the early 90's offers high performance detection along with wavelength selectivity: resonant cavity enhanced (RCE) photodetectors. In this thesis, we present our efforts for the design, fabrication and characterization of AlGaAs/GaAs-based Schottky and p-i-n type RCE photodiodes operating within the first optical communication window. Epitaxial wafers are designed using scattering matrix method based simulations and grown with molecular beam epitaxy. Schottky photodiode was primarily designed for high-speed operation, where as in p-i-n structure we aim to achieve near unity quantum efficiency. Measurement results show reasonable agreement our theoretical simulations. Fabricated Schottky and p-i-n RCE photodiode samples demonstrated high bandwidth-efficiency products, 36 and 46 GHz respectively. These results indicate the best performances for RCE Schottky and p-i-n photodiodes reported in scientific literature.Item Open Access ITO-schottky photodiodes for high-performance detection in the UV-IR spectrum(IEEE, 2004) Bıyıklı, Necmi; Kimukin, I.; Butun, B.; Aytür, O.; Özbay, EkmelHigh-performance vertically illuminated Schottky photodiodes with indium-tin-oxide (ITO) Schottky layers were designed, fabricated, and tested. Ternary and quarternary III-V material systems (AlGaN-GaN, AlGaAs-GaAs, InAlGaAs-InP, and InGaAsP-InP) were utilized for detection in the ultraviolet (UV) (λ < 400 nm), near-IR (λ ∼ 850 nm), and IR (λ ∼ 1550 nm) spectrum. The material properties of thin ITO films were characterized. Using resonant-cavity-enhanced (RCE) detector structures, improved efficiency performance was achieved. Current-voltage, spectral responsivity, and high-speed measurements were carried out on the fabricated ITO-Schottky devices. The device performances obtained with different material systems are compared.