Regensburg 2016 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 35: Poster I

HL 35.51: Poster

Dienstag, 8. März 2016, 15:00–19:00, Poster A

Growth kinetics of GaP-nanowires employing TBP and TMGa — •Matthias Steidl, Christian Koppka, Peter Kleinschmidt, and Thomas Hannappel — TU Ilmenau, Institute of Physics, Department of Photovoltaics, Gustav-Kirchhoff-Str. 5, D-98693 Ilmenau, Germany

III-V nanowires (NWs) are promising candidates as components of future third generation photovoltaic devices and solar water splitting cells. Here, the moderately high band gap (Eg=2.3eV) and stability in many electrolytes makes GaP a suitable material. Moreover, by adding As or N the band gap can be tuned making the material highly interesting for tandem devices e.g. with silicon sub cells. While the growth kinetics of GaP and GaAs NWs using PH₃ and AsH₃ are already studied in detail, the growth kinetics of GaP NWs applying TBP have not been thoroughly investigated so far. Here, we report on the influence of V/III ratio, temperature and carrier gas on the Au-assisted VLS growth of GaP NWs by MOVPE. We found a great impact of the temperature on the growth behaviour. For low temperatures (450^∘C) the NW length does not increase linear with time - the longer the NW the smaller its growth rate (GR). In contrast, above 475^∘C, the GR is constant. The GR reaches its maximum at around 488^∘C and decreases above. As no Arrhenius dependency can be derived, the growth kinetics in this parameter regime are not governed by only one rate determining step. Moreover, a linear dependency of the GR on the V/III ratio (=5-20) was found for 450^∘C. Here, changing the carrier gas from pure H₂ to a mixture of H₂/N₂ increases the GR by a factor of two.