Browsing by Subject "Silicon germanium"
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Item Open Access Plasmonic nanoslit array enhanced metal-semiconductor-metal optical detectors(Institute of Electrical and Electronics Engineers, 2012-01-09) Eryilmaz, S. B.; Tidin, O.; Okyay, Ali KemalMetallic nanoslit arrays integrated on germanium metal-semiconductor-metal photodetectors show many folds of absorption enhancement for transverse-magnetic polarization in the telecommunication C-band. Such high enhancement is attributed to resonant interference of surface plasmon modes at the metal-semiconductor interface. Horizontal surface plasmon modes were reported earlier to inhibit photodetector performance. We computationally show, however, that horizontal modes enhance the efficiency of surface devices despite reducing transmitted light in the far field.Item Open Access Silicon-germanium multi-quantum wells for extended functionality and lower cost integration(IEEE, 2010) Onbasli, M.C.; Yesilyurt, Alper; Yu H.Y.; Nayfeh, A.M.; Okyay, Ali KemalSilicon-Germanium quantum wells were grown in p-i-n layers using a recently developed epitaxial technique. Nanostructural characterization (TEM, XPS, photoluminescence) indicates low-dislocation density, high quality films. Solar cells made of these layers have low leakage current. ©2010 IEEE.Item Open Access Synthesis of ultra-small Si / Ge semiconductor nano-particles using electrochemistry(Elsevier, 2012) Alkis, S.; Ghaffari, M.; Okyay, Ali KemalIn this paper, we describe the formation of colloidal Si/Ge semiconductor nano-particles by electrochemical etching of Ge quantum dots (GEDOT), Silicon-Germanium graded layers (GRADE) and Silicon-Germanium multi-quantum well (MQW) structures which are prepared on Silicon wafers using low pressure chemical vapor deposition (LPCVD) technique. The formation of Si/Ge nano-particles is verified by transmission electron microscope (TEM) images and photoluminescence (PL) measurements. The Si/Ge nano-particles obtained from GEDOT and GRADE structures, gave blue emissions, upon 250 nm, and 300 nm UV excitations. However, the nano-particles obtained from the MQW structure did exhibit various color emissions (orange, blue, green and red) upon excitation with 250 nm, 360 nm, 380 nm and 400 nm wavelength light.