Electrodeposition of CdSe on nanopatterned pillar arrays for photonic and photovoltaic applications

This work investigates the electrodeposition of CdSe photonic nanostructures into two dimensional (2D) resist templates generated by X-ray lithography. This templated electrolytic infiltration process is particularly interesting for photonic and photovoltaic applications. Both current and voltage controlled electrochemical depositions have been performed to infiltrate CdSe onto the 2D templates. Followed by the removal of the template, triangular arrays of CdSe pillars or networks with more than 1 μm in height were obtained. The detailed studies of deposition parameters such as applied voltage, current density, deposition time, concentrations of electrolytes and temperatures were carried out to determine the optimum conditions to obtain high quality 2D CdSe photonic crystals (PhCs). The full optical and structural characterization of the CdSe nanostructures showed that the CdSe films prepared have a cubic structure with nanometer grain size. Optical absorption studies reveal a bandgap of 2.1 eV for the thin film grown CdSe, blue-shifted from the characteristic 1.7 eV of bulk CdSe, resulting from size quantization effect. Preliminary optical characterization by a micro-reflectance technique is performed in order to assess the performance of the fabricated samples as 2D PhCs.