Metal-assisted Chemical Etching Of Silicon And Application In Hybrid Solar Cells

Due to their unique optical, electrical and thermoelectric properties, siliconnanowires(SiNW) have promissing application potentials in fields such asphotoelectric devices and sensors. Here we fabricated large area SiNW array andapplied them into organic-inorganic hyrid solar cells.1. We fabricated SiNW and Si nanohole by the combination of metal annealingprocess and chemical wet etching of Si. Depending on thermodynamics analysis, therewere two main factors playing vital roles in the morphology of the metal: thickness ofmetal film and annealing temperature. Nanowires/nanoholes could be achieved viaetching from metal films with regular holes/hemispherial metal particles.2. Precise control over parameters of SiNW was achieved by nanospherelithography method. Gold film with regular holes was prepared on Si wafer to fabricatevertically alligned SiNW arrays. The diameter and length of the SiNW were tuned bydiameters of the holes and the etching time, respectively. The anti-reflection propertyof SiNW arrays could be adjusted by changing their diameter, length and period.3. We fabricated Si-PEDOT:PSS hybrid photovoltaic devices and investigated theinterface effects of SiNW. By comparing device performance based on SiNW treatedwith TMAH and methylation, we found that devices treated with methylation showedlower dark currents and a28%enhancement in efficiency than TMAH ones. Theoptimal device processed in PCl5for2h got the best efficiency of12.00%. Analysis ofdark current, optical simulation and mapping of device voltage and current offered better understanding of the function of SiNW in hybrid solar cells.