Material Science and Engineering

Biography

Biography: Shanthi Iyer

Abstract

Semiconductor nanowires (NWs) are currently creating a significant impact in the electronics and optoelectronic research fields due to their intrinsic one dimensional architecture along with a “nano” dimensional contact enabling greater flexibility in band-gap engineering and material design architecture, leading to novel and unique opto-electronic properties. Thus planar NWs represent a new paradigm with advanced nanoheterostructure configurations that is inconceivable in thin films, opening up opportunities for transformational improvements particularly in optoelectronic devices. NW applications in optoelectronics are still evolving. In particular, wavelengths in the telecommunication wavelength region of 1.3-1.55 µm, have been of great interest for potential use in optoelectronic devices for photonic integrated circuits as well as in single photon detection for optical quantum information applications. In this talk, growth of dense and vertical oriented ternary and quaternary III-V heterostructured nanowires of GaAsSb(N) on (111) Si by vapor-liquid-solid (VLS)/vapor-solid (VS) mechanisms via self-catalyzed molecular beam epitaxy will be presented. Band gap tuning up to 1.3 µm in GaAs/GaAsSb(N) has been realized in core-shell heterostructured nanowires by varying the Sb(N) content. All the NWs exhibit zinc blende structure. Our preliminary results using Raman and temperature dependence of PL spectroscopy along with the corresponding Schottky barrier heights indicated NW configuration to be a better template for efficient annihilation of the N induced point defects in dilute nitride NWs in comparison to its thin film counterpart. The improvements in the µ-photoluminescence characteristics due to the surface passivation by GaAlAs shell and chemical passivation and its impact on the noise characteristics of the PIN device will be presented.