Abstract
This work focuses on the extraction of the open circuit voltage (VOC) on photovoltaic nanowires by surface photovoltage (SPV) based on Kelvin probe force microscopy (KPFM) measurements. In a first approach, P-I-N radial junction (RJ) silicon nanowire (SiNW) devices were investigated under illumination by KPFM and current-voltage (I-V) analysis. Within 5%, the extracted SPV correlates well with the VOC. In a second approach, local SPV measurements were applied on single isolated radial junction SiNWs pointing out shadowing effects from the AFM tip that can strongly impact the SPV assessment. Several strategies in terms of AFM tip shape and illumination orientation have been put in place to minimize this effect. Local SPV measurements on isolated radial junction SiNWs increase logarithmically with the illumination power and demonstrate a linear behavior with the VOC. The results show notably that contactless measurements of the VOC become feasible at the scale of single photovoltaic SiNW devices.
Highlights
Semiconductor nanostructures attract a great deal of research interest because of their nanoscale properties that offer a great potential for improving performances in existing devices
These results show the difficulties to perform Kelvin probe force microscopy (KPFM) measurements under real dark conditions when in particular the laser beam-based deflection system (LBBDS) wavelength can interact with the sample
Completed devices based on radial junction (RJ) silicon nanowire (SiNW) were jointly analyzed under illumination by illumination by KPFM and current-voltage (I-V) and KPFM measurements
Summary
Semiconductor nanostructures attract a great deal of research interest because of their nanoscale properties that offer a great potential for improving performances in existing devices. The efficiency of nanowire solar cells may be limited by damaged nanowire junctions in the array; efficiencies up to 9.6 % have been already demonstrated for silicon nanowire (SiNW) RJs based on Si thin-film technology [3]. The characterization of such structures remains a critical issue, and notably the possibility to characterize the photoelectrical performances of individual nanowires is an added value for the improvement of the final device. KPFM analysis on PV nanodevices is not straightforward notably due to that it can require to perform measurements in both dark and illumination conditions to extract the surface potential variation, named surface photovoltage (SPV)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
