MOCVD or "metalorganic chemical vapour deposition" is a technique for depositing very thin layers of compound semiconductor materials with extremely fine precision, approaching single atomic layer control. It is used commercially in a wide variety of electronic devices including cell phones, solar cells, photodetectors, light emitting diodes,  and lasers. Currently the primary research activity involves the growth and characterization semiconducting nanowires and devices.

The MOCVD lab supports a wide range of research projects ranging from basic crystal growth mechanisms to physics of semiconductors to the development of semiconductor devices that push the limits of what is currently available. The work is highly interdisciplinary and support projects in nanoscience, magnetism, optoelectronics, electronic devices, and new materials. Some specific examples are given below:

1. Growth and morphology control of III-V semiconductor nanowires for prototype device applications
There is intense worldwide effort into the studies of the properties and growth of semiconductor nanowires. My group has recently begun an effort in this area to grow III-V nanowires by the vapour-solid-liquid mechanism using Au catalyst nanoparticles. We have discovered that the crystal growth of nanowires can be controlled in a simple fashion by using precursor chemistry to control the transition between axial and lateral growth. This opens up the means to fabricate a variety of core shell structures for potential applications in photovoltaics and FET devices.

2. Doping and electrical characterization of semiconductor nanowires
The control of doping and the measurement of electrical properties is one of the great challenges in semiconductor nanowire growth and device applications. Our group has specialized recently in developing techniques for characterizing electrical properties of nanowires using a nanoprobe in a scanning electron microsope. This non-destructive technique allows us to measure a surprising range of materials parameters including majority carrier electrical properties, surface passivation effects, and junction properties of axial and core-shell junctions. Recently we hjave extended this technique to electron beam induced current measurements of axial and core-shell nanowire junctions.

3. Growth of ZnO nanowires and thin films by metalorganic chemical vapour deposition
ZnO has a received a great deal of recent interest as an optoelectronic material, primarily as a potential replacement for GaN in UV-visble light emitting diodes. OMVPE is one of the leading contenders amongst several growth techniques; however, significant challenges exist. Our work focusses on trying to understand the incorporation of donor and acceptor impurities in this material. We have demonstrated the growth of epitaxial ZnO nanowires on sapphire with extremely sharp low temperature photoluminescence linewidths, comparable to the highest quality bulk substrate materials. We are currently exploring the properties of n- and p-dopants in both planar ZnO films and self assembled nanowires in order to compare the contributions of native and extrinsic impurities on the electrical properties.  We have succeeded in identifying several new shallow donor species in this material and work is underway to understand the microscopic structure of these defects. We have recently developed the capability to perform selective excitation photoluminescence spectroscopy using a tunable UV source. This will enable clearer understanding of the photoluminescence spectra of this important material.

4. Growth of narrow gap materials for optical detector applications
This work studies the feasibility of type II superlattices based on a little explored material combination for application to “third generation” (multicolor) mid IR focal plane array detectors. Strain balanced superlattices of InAsSb and InAs were shown to have optical emission out to 7 microns, well beyond the wavelength of InSb.