title: Optical and electrical study of core-shell silicon nanowires for solar applications.
abstract: In this work, we report a CMOS comparable fabrication process of core-shell SiNW solar cell from single-crystalline p-type Si(100) test wafers. Optical lithography defined plasma etching was used to form highly ordered vertical SiNW arrays, which display a drastic reduction in optical reflectance over a wide range of wavelengths. BF(2) and P ion implantations were employed for producing a sharp and shallow radial p-n junction. Under AM 1.5G illumination, the device demonstrates a short circuit current density (Jsc) of 14.2 mA/cm(2), an open circuit voltage (Voc) of 0.485 V and a fill factor (FF) of 42.9%, giving a power conversion efficiency (PCE) of 2.95%. The Jsc observed is 52% higher than that in the control device with planar Si p-n junction, indicating significant enhancement in carrier generation and collection efficiency from the core-shell structure. Impact of series resistance (Rs) is also studied, highlighting potential improvement of PCE to 4.40% in the absence of Rs. With top contact optimized, PCE could further increase to 6.29%.
authors.affiliation: Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore.
authors.forename: Zhenhua
authors.initials: Z
authors.lastname: Li
authors.forename: Jian
authors.initials: J
authors.lastname: Wang
authors.forename: Navab
authors.initials: N
authors.lastname: Singh
authors.forename: Sungjoo
authors.initials: S
authors.lastname: Lee