Strain loading dependent optoelectronic characteristics in CdS micro/nanowires

Abstract

Strain engineering is considered as one efficient approach to adjust the fundamental properties of semiconductor nanostructures that are potential in advanced smart devices. Directly assessing the strain effect on the properties of nanostructures thus becomes intensely important. In this article, we report strain-induced photodetection decline and bandgap modulation in buckled CdS micro/nanowires with high-quality crystallinity. The strain generated by artificially bending leads to a sharp (two orders of magnitude) decrease of the photoresponse in comparison with strain-free parts, due to a strain-induced reduction in electrical conductivity. Cathodoluminescence (CL) spectroscopic measurements on in-plain buckled CdS micro/nanowires provide direct visualization of deformation-induced strain in the curved zones, from which the linear red-shift of the near band edge luminescence versus local strain (ε = 2.27–8.30%) corresponds a deformation potential of −8.5 ± 1 meV/%. These observations support a view of strain engineering as an enabling tool to both explore novel physics in semiconductors and to tune their optical and electronic properties.