Title :
GaP/Si wire array solar cells
Author :
Tamboli, Adele C. ; Turner-Evans, Daniel B. ; Malhotra, Manav ; Kelzenberg, Michael D. ; Atwater, Harry A.
Author_Institution :
Thomas J. Watson Labs. of Appl. Phys., California Inst. of Technol., Pasadena, CA, USA
Abstract :
Si wire arrays have recently demonstrated their potential as photovoltaic devices. Using these arrays as a base, we consider a next generation, multijunction wire array architecture consisting of Si wire arrays with a conformal GaNxP1-x-yAsy coating. Optical absorption and device physics simulations provide insight into the design of such devices. In particular, the simulations show that much of the solar spectrum can be absorbed as the angle of illumination is varied and that an appropriate choice of coating thickness and composition will lead to current matching conditions and hence provide a realistic path to high efficiencies. We have previously demonstrated high fidelity, high aspect ratio Si wire arrays grown by vapor-liquid-solid techniques, and we have now successfully grown conformal GaP coatings on these wires as a precursor to considering quaternary compound growth. Structural, optical, and electrical characterization of these GaP/Si wire array heterostructures, including x-ray diffraction, Hall measurements, and optical absorption of polymer-embedded wire arrays using an integrating sphere were performed. The GaP epilayers have high structural and electrical quality and the ability to absorb a significant amount of the solar spectrum, making them promising for future multijunction wire array solar cells.
Keywords :
Hall effect; III-V semiconductors; X-ray diffraction; absorption coefficients; coatings; elemental semiconductors; gallium compounds; light absorption; polymers; semiconductor epitaxial layers; silicon; solar cell arrays; GaP epilayers; GaP-Si; GaP-Si wire array heterostructures; GaP-Si wire array solar cells; Hall measurement; X-ray diffraction; conformal GaP coating; illumination angle; multijunction wire array architecture; optical absorption; optical device physics simulations; photovoltaic devices; polymer embedded wire arrays; quaternary compound growth; solar spectrum; thickness coating; vapor liquid solid techniques; Absorption; Arrays; Optical reflection; Photonic band gap; Photovoltaic cells; Silicon; Wire;
Conference_Titel :
Photovoltaic Specialists Conference (PVSC), 2010 35th IEEE
Conference_Location :
Honolulu, HI
Print_ISBN :
978-1-4244-5890-5
DOI :
10.1109/PVSC.2010.5614159