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Thursday, 05 February 2015

Dr. Reza Sanatinia offered an ICN2 Seminar on III-V Semiconductor Nanopillars for Photovoltaics and Nonlinear Optics

Optical properties of semiconductor nanowires/nanopillars, as individual or ensemble, have attracted significant research interest in recent years. Dr. Reza Sanatinia, from the KTH Royal Institute of Technology in Stockholm (Sweden) and Visiting scientist at the ICN2 Phononic and Photonic Nanostructures Group, offered an INC2 Seminar about these structures and their applications.

Optical properties of semiconductor nanowires (NWs)/nanopillars (NPs), as individual or ensemble, have attracted significant research interest in recent years. Their potential applications range from solid-state lighting, photovoltaics, lasing and nonlinear optics to sensing and life sciences. NW/NP geometries with enhanced electric fields and tight confinement of optical modes make them ideal for these applications. Many of III-V NWs/NPs are particularly interesting for optoelectronic and photovoltaic applications, because of their direct band gap, high refractive index, superior electrical properties and high second order nonlinearity coefficients. Dr. Reza Sanatinia, from the Department of Material and Nanophysics at the KTH Royal Institute of Technology in Stockholm (Sweden) and Visiting scientist at the ICN2 Phononic and Photonic Nanostructures Group, offered on January 28 an INC2 Seminar about these structures and their applications.

The focus of the talk was on III-V NPs, their optical properties and applications for photovoltaics and nonlinear optics. Different methods for fabrication of NPs (top-down approach) were proposed. The fabricated NPs show a broadband suppression of reflectance, which is particularly an interesting feature for photovoltaic applications. Moreover, a unique wafer-scale self-organization process for generation of InP NPs is demonstrated. As a proof of concept, the self-organized InP NPs were used to fabricate solar cell devices.

Second-harmonic generation (SHG) was experimentally observed and analyzed from GaP NP waveguides (single and in arrays) with vertical geometry. In case of individual NPs, SHG was analyzed considering different modal excitations in GaP NPs, where it is possible to alter the field distribution of the radiated SHG light. These findings, suggest that SHG light from single GaP NPs are promising candidates for ultrafast light sources at nanoscopic scale, with potential applications in sensing, bio and single cell/ molecular imaging.