Open AccessGe nanopillar solar cells epitaxially grown by metalorganic chemical vapor deposition
Author(s) -
Young-Jo Kim,
Nguyễn Đình Lâm,
Kangho Kim,
Won-Kyu Park,
Jaejin Lee
Publication year - 2017
Publication title -
scientific reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.24
H-Index - 213
ISSN - 2045-2322
DOI - 10.1038/srep42693
Subject(s) - nanopillar , materials science , optoelectronics , epitaxy , metalorganic vapour phase epitaxy , ohmic contact , passivation , chemical vapor deposition , energy conversion efficiency , nanosphere lithography , solar cell , etching (microfabrication) , nanotechnology , layer (electronics) , fabrication , nanostructure , medicine , alternative medicine , pathology
Radial junction solar cells with vertically aligned wire arrays have been widely studied to improve the power conversion efficiency. In this work, we report the first Ge nanopillar solar cell. Nanopillar arrays are selectively patterned on p-type Ge (100) substrates using nanosphere lithography and deep reactive ion etching processes. Nanoscale radial and planar junctions are realized by an n-type Ge emitter layer which is epitaxially grown by MOCVD using isobutylgermane. In situ epitaxial surface passivation is employed using an InGaP layer to avoid high surface recombination rates and Fermi level pinning. High quality n-ohmic contact is realized by protecting the top contact area during the nanopillar patterning. The short circuit current density and the power conversion efficiency of the Ge nanopillar solar cell are demonstrated to be improved up to 18 and 30%, respectively, compared to those of the Ge solar cell with a planar surface.