Macroscopic-nanoscopic approach for the investigation of Semiconducting nanoparticles

Speaker
Yehonadav Bekenstein, Hebrew University
Date
22/01/2015 - 15:30 - 14:30Add to Calendar 2015-01-22 14:30:00 2015-01-22 15:30:00 Macroscopic-nanoscopic approach for the investigation of Semiconducting nanoparticles The study of electrical properties of semiconducting nanocrystals (NCs) poses fundamental as practical difficulties. While control of the optical characteristics of these objects by size and shape is well understood, precise modification of the electronic properties, beyond the band-gap, is still challenging. We have taken a combined macroscopic-nanoscopic approach to investigate the electronic properties of Cu­2S NCs. First, a semiconductor-metallic hybrid structure, comprising a Cu2S NC encapsulated by a Ruthenium cage-like shell. The growth of a metallic component induces semiconductor metallic synergistic behavior and unique negative differential conductance features in the tunneling spectra. Second, we discovered a new impurity free mechanism for NC doping, by thermal treatment at moderate temperatures, thus creating vacancies leading to free charge carriers. This thermal doping method is applied to Cu2S-NC arrays, where Cu vacancies easily form, resulting in p-type doping and achieving up to 6 orders of magnitude conductance enhancement. We succeeded also in demonstrating local thermal doping via a focused laser beam serving as the heating source, opening an innovative route for low-temperature patterned doping of NC arrays.   “Thermal doping by vacancy formation in copper sulfide nanocrystal arrays”, K.Vinokurov, S.Keren-Zur, I. Hadar, Y. Schilt, U. Raviv, O.Millo, U.Banin, NanoLetters,2014,  DOI:10.1021/nl4043642 “Periodic negative differential conductance in a single metallic nanocage” Y.Bekenstein, K.Vinokurov, TJ.Levy, E.Rabani, U.Banin, O.Millo Physical Review B 86 (8), 085431(2012) “Electronic properties of hybrid Cu2S/Ru semiconductor/metallic-cage nanoparticles” Y.Bekenstein, K.Vinokurov, U.Banin, O.Millo Nanotechnology 23 (50), 505710(2012) “Charge transport in Cu2S nanocrystal arrays a study of crystal size and ligand length”, O.Elimelech, K.Vinokurov, O.Millo, U.Banin  Zeitschrift für Physikalische Chemie (2014) Resnick Building 209, room 210 המחלקה לפיזיקה physics.dept@mail.biu.ac.il Asia/Jerusalem public
Place
Resnick Building 209, room 210
Abstract

The study of electrical properties of semiconducting nanocrystals (NCs) poses fundamental as practical difficulties. While control of the optical characteristics of these objects by size and shape is well understood, precise modification of the electronic properties, beyond the band-gap, is still challenging. We have taken a combined macroscopic-nanoscopic approach to investigate the electronic properties of Cu­2S NCs. First, a semiconductor-metallic hybrid structure, comprising a Cu2S NC encapsulated by a Ruthenium cage-like shell. The growth of a metallic component induces semiconductor metallic synergistic behavior and unique negative differential conductance features in the tunneling spectra. Second, we discovered a new impurity free mechanism for NC doping, by thermal treatment at moderate temperatures, thus creating vacancies leading to free charge carriers. This thermal doping method is applied to Cu2S-NC arrays, where Cu vacancies easily form, resulting in p-type doping and achieving up to 6 orders of magnitude conductance enhancement. We succeeded also in demonstrating local thermal doping via a focused laser beam serving as the heating source, opening an innovative route for low-temperature patterned doping of NC arrays. 

  1.  “Thermal doping by vacancy formation in copper sulfide nanocrystal arrays”, K.Vinokurov, S.Keren-Zur, I. Hadar, Y. Schilt, U. Raviv, O.Millo, U.Banin, NanoLetters,2014,  DOI:10.1021/nl4043642
  2. “Periodic negative differential conductance in a single metallic nanocage”
    Y.Bekenstein, K.Vinokurov, TJ.Levy, E.Rabani, U.Banin, O.Millo
    Physical Review B 86 (8), 085431(2012)
  3. “Electronic properties of hybrid Cu2S/Ru semiconductor/metallic-cage nanoparticles”
    Y.Bekenstein, K.Vinokurov, U.Banin, O.Millo
    Nanotechnology 23 (50), 505710(2012)
  4. “Charge transport in Cu2S nanocrystal arrays a study of crystal size and ligand length”, O.Elimelech, K.Vinokurov, O.Millo, U.Banin  Zeitschrift für Physikalische Chemie (2014)

תאריך עדכון אחרון : 11/11/2014