Doping- and size-dependent photovoltaic properties of p-type Si-quantum-dot heterojunction solar cells: correlation with photoluminescence

摘要

Boron-doped SiOx /SiO2 superlattices have been prepared on n-type Si u0002100u0003 wafers by ion beamnsputtering and subsequently annealed to form p-type Si quantum dots u0002QDsu0003-type Si-wafernheterojunction solar cells. Systematic studies on photoluminescence u0002PLu0003 and photovoltaic effectsnshow that optimum formation of Si QDs, proper doping concentration u0002nBu0003, and minimization ofndefects are crucial factors for enhancing energy-conversion efficiency of the solar cells. Highestnefficiency of 9.5% is obtained under the conditions of x=1.0 u0002QD size: u00045nmu0003 and nB=6.3nu00021020ncm−3n. Possible physical mechanisms are discussed to explain the correlation of thenphotovoltaic parameters and the QD-/defect-PL intensities. The demonstration of the photovoltaicneffects in the Si-QD heterojunction solar cells is promising for the development of next-generationnall-Si-QD solar cells. © 2010 American Institute of Physics. u0005doi:10.1063/1.3480609