\chapter{Conclusions} \label{chapter_conclusion}

\begin{enumerate}

\item We fabricated a range of nanostructured metallic thin films on both Si and glass substrates using evaporative techniques. These films have been characterised using a combination of electronic and optical spectroscopy techniques.

\item Secondary electron microscopy analysis reveals striking differences in the structure of Au and Black Au films; Au films have been shown to consist of a regular periodic array of nanoparticles, whilst Black Au appears to consist of a highly randomised, porous mix of strand like structures.

\item A Total Current Spectroscopy experiment for characterisation of samples in situ has been integrated with the technology for sample preparation. We used this setup to investigate elastic scattering of electrons as a function of film deposition. 
\begin{itemize}
	\item Results for Black metal films deposited on existing layers of metal films suggest that the Black metal films present a sharper, more step like potential barrier to the primary electrons. 
	\item Further improvements may be made to the Total Current Specroscopy experiment with a possibility to investigate inelastic scattering processes occuring in the metallic thin films.
\end{itemize}

\item 
The optical properties of Black Au have been investigated and compared with those of Au. 
\begin{itemize}
	\item Transmission spectroscopy experiments support existing evidence for a plateau in the infra-red.
	\item We found a minima in the transmission spectrum of a Black Au film at around $370$nm; this minima is absent in the spectrum of a similar thickness Au film. 
\end{itemize}

\item Ellipsometry has been used to determine the optical constants of thin films of Ag and Black Ag. These results show a significant peak in both the refractive index and extinction coefficient of the Black Ag film in the region of $350$ to $400$nm. These peaks are absent for the Ag sample.

\end{enumerate}