Browsing by Subject "Materials science and technology"

Filter results by typing the first few letters
Now showing 1 - 3 of 3
  • Thumbnail Image
    ItemOpen Access
    Experimental and computational analyses of electroabsorption in polar InGaN/GaN quantum zigzag heterostructures
    (IEEE, 2008-11) Sarı, Emre; Özel, Tuncay; Koç, Aslı; Ju, J.-W.; Ahn, H.-K.; Lee, I.-H.; Baek, J. H.; Demir, Hilmi Volkan
    Traditional quantum confined Stark effect is well known to lead to strong electroabsorption in multiple quantum well (MQW) structures, yielding only red-shift of the absorption edge with the externally applied electric field, independent of the direction of the applied field. However, a little is known the electroabsorption behavior in III nitride quantum structures grown on c-plane of their wurtzite crystal structure, which is substantially different than the electroabsorption of conventional quantum structures. Such III-N heterostructures exhibit strong polarization fields and discontinuity of such polarization fields at their heterointerfaces causes stimulation of large electrostatic fields in alternating directions for their wells and barriers. Consequently, their energy band diagrams form a zigzag potential profile in conduction and valence bands, instead of those with square profiles. A natural and suitable approach for understanding these polarization fields and also developing insight to design related devices (e.g., electroabsorption modulators) is to study electroabsorption behavior as a function of the polarization field in such polar structures. To this end, we present a comparative, computational and experimental study of electroabsorption in our different designs of c-plane grown polar InGaN/GaN quantum structures with varying levels of polarization.
  • Thumbnail Image
    ItemOpen Access
    Multi-material specific, targeted self-assembly of nanocrystal emitters using genetically engineered peptides on optoelectronic microchips
    (IEEE, 2008-11) Zengin, Güliş; Şeker, U. O. S.; Koç, Aslı; Mutlugün, Evren; Akyüz, Özgün; Sarı, Emre; Sarıkaya, M.; Tamerler, C.; Demir, Hilmi Volkan
    We demonstrated material-specific binding of the quantum dot emitters hybridized with GEPI on multi-material patterned microchips. These proof-of-concept results open up new opportunities in nanophotonics, allowing for more specific and controlled assembly of quantum dots in optoelectronic devices and building of novel molecular organic-inorganic hybrid devices
  • Thumbnail Image
    ItemOpen Access
    Nanocrystal emitters for enhanced photovoltaics in UV
    (IEEE, 2008-11) Mutlugün, Evren; Soğancı, İbrahim Murat; Demir, Hilmi Volkan
    [No abstract available]