Surface Science and Technology Group : School of Chemistry, University of Melbourne

Surface Science and Technology Group

Nanostructuring of Advanced Materials

Synthesis of precursors for single source chemical vapour deposition (SSCVD)

Single source chemical vapour deposition utilizes specialized precursors which contain a core of the components of the desired film (as shown in figure 1). This core is surrounded by organic ligands which impart volatility to the compound. When the precursor is sublimed under vacuum conditions onto a heated substrate the ligands surrounding the core decompose and a film is grown. This technique utilizes a simple experimental setup but requires specialized precursors.

This part of the project involves developing new precursors for SSCVD film growth. Films including ZnO, ZnS and MgO have been grown using this technique. New precursors are being developed to improve the properties of the films obtained as well as to begin depositing other types of films.

Nucleation mechanisms of semiconductor films

Semiconductor films grown using the SSCVD method described above have been examined using various microscopy techniques including SEM and TEM. It has been found that the film nucleation mechanisms described for sputtered films do not fully describe the microstructure of films grown using SSCVD.

The effect of substrate geometry on film growth has also been investigated including oblique deposition and the effect of substrate curvature. Figure 2 shows a TEM image of a ZnO film.

Deep Level Defects in ZnO

The phenomena of lasing from random materials is not well understood. It is thought that defects within the material may act as an optical cavity amplifying light in place of the mirrors used in conventional lasers. In this study we look at the defects produced in ZnO films using the SSCVD method of film growth. The origins of the defects have been investigated using cathodoluminescence and synchrotron techniques such as EXAFS. Assigning defect emissions is not straightforward and this project is ongoing.

If the defect mechanisms can be understood then it may be possible to enhance light emission from these random media and hence create reliable lasers from disordered materials.


Figure 1 - SSCVD precursor.	Figure 2 - Transmission electron micrograph of zinc oxide film.

Research Groups