Forschungsprojekte

Research Group FOR 1616:

“Dynamics and Interactions of Semiconductor Nanowires for Optoelectronics“
E1: Electrically pumped III/V nanowire light emitters

01.03.2012 – 28.02.2018


Acronym: FOR 1616
Scientists: Claudia Speich, Christian Blumberg, Werner Prost

Introduction

The use of nanowire pn-junctions for electrical stimulated light emission is proposed. Modulation doped GaAs-based nanowires provide a high injection of both electrons and holes, respectively. Axial and radial lattice-(mis)matched heterostructures enable band-gap and refractive index engineering for electrical and optical confinement. In the first period highly conductive p- and n ohmic contacts for future intense electrical stimulated light emission were realized while limitations in carrier lifetime identified. For GaN-based core-shell nanowire LED the long lifetime in c-plane was cancelled by using m-plane junction leadung to a new LED speed record [1]. The high density of surface states of the GaAs nanowires will be tackled both by radial growth of wide band gap epitaxial layers and by surface engineering using dielectric coating, and chemical treatment. In-situ controlled optical doping with a single dopant using i. e. Europium implantation will be used for ultra-small axial light emitters as a possible step towards single photon emission. The main goal of the project is the realization of electrically stimulated lasing based on photonic mode design and in strong collaboration with exited-state lifetime measurements.

Work plan

This projects aims for electrically stimulated light emitters using on GaAs based nanowire pn junctions. We propose to extend the project with work packages in direct collaboration with specific partners of the priority programme but with the focus on electrically stimulated light emitters and lasing.

Nanowire LED

  • Rare earth recombination center LED
  • Wet chemical surface treatment of GaAs based nanowires

Nanowire LASER

  • Core-shell LASER

The waveguide properties of bare GaAs nanowires and it is use as a cavity have been tested [2]. The stimulating light was adjusted perpendicular to the wire center. At the end facets of the wires with a diameter of d > 250 nm strong Fabry–Perot oscillations have been observed at 79 K for an intensity of P ˜ 100 W/cm² (cf. Fig. 1). The oscillation can be used to calculate a modified resonator quality factor Q=420 [3] were lambda C to the mode center frequency and lambda_FWHM corresponds to the full-width half-maximum of the mode.

Figure 1: Measured luminescence at T = 79 K of a GaAs/AlGaAs nanowire (L = 17.9 µm, d = 315 nm) under central vertical optical excitation (lambda = 532 nm, I = 183 W/cm²): (a) luminescence at the right facet (blue), left facet (red), and from the center (black), (b) inset shows the total intensity at the facets and in the center, and in (c) the data of (a) are plotted with normalized intensity [2].
Heterointegration of III/V light emitting devices

  • Field-assisted assembly

The field-assisted self-assembly (FASA) technology onto a host substrate such as Si (100) has been investigated for InAs NW MISFET [4] and for GaAs nanowires (cf Fig. 2]. The nanowires were aligned with an external electric field applied ot he electrodes by the dielectrophoretic force F_DEP [5]. This force depends on the geometrical, dielectric and conductive properties of the nanowire and on the applied bias are the length and the radius of a nanowire, e_l the dielectric constant of the liquid, ?(E^2) the gradient of the square of the applied electric field and Re{C} the real part of the Clausius-Mosotti factor [6].

Figure 2: Schematic of FASA: The electric field induces a dipole in the NW, leading to a movement, alignment and finally to a deposition of the wire between the contact pairs.

References

  1. High-Speed GaN/GaInN nanowire array LED on Silicon (111), R Köster, D Sager, W A Quitsch, O Pfingsten, A Poloczek, S Blumenthal, G Keller, W Prost, G Bacher, F-J Tegude; Nano Lett. 15 (4), 2318–2323, 2015.
  2. Thorsten Wierzkowski, Lichtemission aus GaAs Nanodrähten für Laseranwendungen, Masterthesis, University Duisburg-Essen, July 2013.
  3. Recombination dynamics in single GaAs-nanowires with an axial heterojunction: n- versus p-doped areas, D Sager, C Gutsche, W Prost, F-J Tegude, G Bacher, J. Appl. Phys. 113, 174303 (2013).
  4. InAs nanowire circuits fabricated by field-assisted self-assembly on a host substrate, K Blekker, R Richter, R Oda, S Taniyama, O Benner, G Keller, B Münstermann, A Lysov, I Regolin. T Waho, W Prost; IEICE TRANS. ELECTRON., vol. E95-C, no. 8, p.1369-1375, 2012.
  5. P A Smith, C D Nordquist, T N Jackson, T S Mayer, B R Martin, J Mbindyo, T E Mallouk, Electric-field assisted assembly and alignment of metallic nanowires. Appl. Phys. Lett., 77 (9) 1399-1401, 2000.
  6. J J Boote, S D Evans, Dielectrophoretic manipulation and electrical characterization of gold nanowires. Nanotechnology 16, 1500-1505, 2005.

Partner

  • Friedrich-Schiller-Universität Jena, Prof. Dr. Carsten Ronning
  • Johannes Gutenberg-Universität Mainz, Prof. Dr. Siegfried Waldvogel
  • Universität Leipzig, Dr. Rüdiger Schmidt-Grund, Prof. Dr. Marius Grundmann
  • Technische Universität Braunschweig, Prof. Dr. Tobias Voss
  • Friedrich-Schiller-Universität Jena, Prof. Dr. Ulf Pesche l

Supported by

  • DFG - Deutsche Forschungsgemeinschaft

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