| dc.description.abstract | There is an urgent need for high-quality fluorescent nanodiamonds for applications in biosensing and quantum information. Existing techniques provide poor diamond quality, making them unsuitable for most applications. The only exception is to etch bulk diamonds by lithography, but this is complex and not scalable to large quantities of nanodiamonds.
For bulk diamonds, the most successful growth techniques are chemical vapor deposition (CVD) and high-pressure, high-temperature (HPHT). However, for nanodiamonds, CVD is not scalable because it is surface-based. Therefore HPHT is the best option. While many decades of research have led to reliable techniques to grow high-quality bulk diamonds by HPHT, nanodiamonds have only recently been researched.
Developing novel nanodiamond growth techniques with large HPHT presses is hampered by the lack of good, real-time diagnostics. Many experiments must be performed, stopped at different times, to get a good profile of the growth process. To overcome this, diamond anvil cells (DACs) have recently been explored. These have the advantage of real-time diagnostics, and can also incorporate laser heating which in turn can access pressures, growth temperatures, and growth times that cannot be achieved in larger, closed presses.
The aim of this master’s project was to investigate and improve all aspects of DAC design for future diamond growth, especially with laser heating. This includes novel DAC hardware design, real-time pressure control, different gasket and culet designs, improved loading and unloading techniques, as well as a variety of laser wavelengths and types for both heating and diagnostics. | |
