Scanning Electron Microscopy

Morphological examination was performed with Scanning Electron Microscopy (SEM). Samples were mounted on aluminum specimen stubs and gold-sputtered to 5 nm thick films to prevent beam charging effects (SC7640 Sputter coater, Quorum Technologies, Kent, UK). High resolution scanning electron microscopic analysis was performed at 20 kV (magnification range of 30,000-120,000×) using a FEI Quanta 200 (FEI, Oregon, USA) microscope and images were processed using the ImageJ software.