Statistically Analyzed Photoresponse of Elastically Bent CdS Nanowires Probed by Light-Compatible In Situ High-Resolution TEM.

Zhang, Chao; Cretu, Ovidiu; Kvashnin, Dmitry G; Kawamoto, Naoyuki; Mitome, Masanori; Wang, Xi; Bando, Yoshio; Sorokin, Pavel B et al. · Nano Lett · 2016

basic_science · Level V

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Abstract

We demonstrate that high resolution transmission electron microscopy (HRTEM) paired with light illumination of a sample and its electrical probing can be utilized for the in situ study of initiated photocurrents in free-standing nanowires. Morphology, phase and crystallographic information from numerous individual CdS nanowires is obtained simultaneously with photocurrent measurements. Our results indicate that elastically bent CdS nanowires possessing a wurtzite structure show statistically unchanged values of ON/OFF (photocurrent/dark current) ratios. Photocurrent spectroscopy reveals red shifts of several nanometers in the cutoff wavelength after nanowire bending. This results from deformation-induced lattice strain and associated changes in the nanowire band structure, as confirmed by selected area electron diffraction (SAED) analyses and density functional tight binding (DFTB) simulations. The ON/OFF ratio stabilities and photocurrent spectroscopy shift of bent CdS nanowires are important clues for future flexible electronics, optoelectronics, and photovoltaics.