C27.

Project title: Cubic boron nitride/diamond composite films

Cubic boron nitride (cBN, a III-V nitride material analogue to diamond) has a set of extreme properties similar to diamond, making it an unique material for many applications extending from tool productions to electronic devices. Cubic BN nitride is the best material for machining steel and other ferrous alloys due to its outstanding chemical stability and hardness. Cubic BN is potentially a superior semiconductor material to diamond as well because both n- and p-type conductivities of cBN are easier to achieve. Nevertheless, the existing methods cannot provide cBN films of the quality required for either mechanical or electronic applications. BN films grown have normally a layered structure with an interfacial amorphous/turbostratic BN (aBN/tBN) layer between substrates and cBN films. Our previous works show that diamond can be used as a universal interlayer to grow pure (i.e., without non-cubic BN interfacial forms), adherent cBN films.
In this project, cBN will be deposited on various kinds of diamond films, including polycrystalline and nanocrystalline, utilizing the fluorine-assisted chemical vapor deposition (CVD) method. The composite films will be characterized by a variety of techniques including FTIR and Raman spectroscopy.

Supervisor:Dr W J Zhang (apwjzh@cityu.edu.hk)

Suitable for: M.Phil. or Ph.D.

Prerequisites: A BSc degree in Physics, Chemistry, Engineering and Materials Science.