Epitaxial growth of GaAs Nanowires on Silicon substrate for photovoltaic applications

Activity: Talks and presentationsConference presentations


Direct bandgap III-V semiconductor nanowires (NWs) grown directly on silicon are very promising materials for optoelectronic and photovoltaic applications [1]. It is well known that it is impossible to grow a monocrystalline planar film of Gallium Arsenide (GaAs) or Indium phosphide (InP) on silicon (Si) without structural defects. However, in case of nanowires these materials can be directly grown on Si with high crystalline quality due to their small footprints and the resulting low stress on the NW/Si interface. Recently it was demonstrated that III-V NW on top of a single junction Si solar cell can greatly improve the power conversion efficiency (PCE) [2]. A PCE of 28,15% can be theoretically obtained in such a GaInP NW/Si tandem solar cell, even considering the possible surface and bulk defects in III-V semiconductors [3].
Here we present selective area non-catalytic metalorganic vapour phase epitaxy (MOVPE) of GaAs NWs on Si (111) substrates. We investigate the influence of growth parameters on GaAs NWs grown through the openings in a Si3N4 mask with a diameter of 200nm and altering pitch. Optimization of the mask etching process improved the yield of vertical standing NWs, which can be seen by comparing fig.1a with 1b. In order to improve the optical properties of a GaAs NW array we investigated different approaches of surface passivation of GaAs NWs. Figure 1c illustrates a 7 times increase of photoluminescence signal from GaAs NWs after surface passivation with GaP monolayer in-situ the MOVPE chamber.

[1]Zhang, Y., et al. (2015). Journal of Physics D: Applied Physics, 48(46).
[2] Trojnar, et al. (2016). IEEE Journal of Photovoltaics, 6(6), 1494–1501.
[3] Wang, Y., et al. (2015). Nanoscale Research Letters, 10(1), 0–4.

Period12 Sept 201814 Sept 2018
Event titleNorthern Optics & Photonics 2018
Event typeConference
LocationLund , SwedenShow on map
Degree of RecognitionInternational


  • Nanowires
  • GaAs
  • silicon
  • epitaxy
  • Material Technology