Today, silicon is the most used material in photovoltaics, with a maximum conversion efficiency getting very close to the Shockley-Queisser limit for single-junction devices. Integrating silicon with higher bandgap ternary III-V absorbers is the path to increase the conversion efficiency. Here, we report on the first monolithic integration of GaxIn(1-x)P vertical 2 nanowires, and the associated p-n junctions, on silicon by the Au-free template-assisted selective epitaxy (TASE) method. We demonstrate that TASE allows for a high chemical homogeneity of ternary alloys through the nanowires. We then show the influence of doping on the chemical composition and crystal phase, the latter previously attributed to the role of the contact angle in the liquid phase in the vapor-liquid-solid technique. Finally, the emission of the p-n junction is investigated, revealing a shift in the energy of the intra-band levels due to the incorporation of dopants. These results clarify some open questions on the effects of doping on ternary III-V nanowire growth and provide the path towards their integration on the silicon platform in order to apply them in next-generation photovoltaic and optoelectronic devices.
KEYWORDS: semiconductor nanowires, GaxIn(1-x)P, template-assisted selective epitaxy, scanning transmission electron microscopy, doping, cathodoluminescence, solar cells
By: Nicolas Bologna, Stephan Wirths, Luca Francaviglia, Marco Campanini, Heinz Schmid, Vasileios Theofylaktopoulos, Kirsten E. Moselund, Anna Fontcuberta i Morral, Rolf Erni, Heike Riel, Marta D. Rossell,
Published in: ACS Applied Materials and Interfaces, volume 10, (no 38), pages 10.1021/acsami.8b10770 in 2018
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