The CVD/STM laboratory at the University of North Texas consists of a hot-tungsten filament CVD growth system attached to a UHV STM system. The CVD system can be used to grow carbon nanotubes, amorphous carbon, diamond-like carbon and diamond films. The films are doped with boron or nitrogen by introducing diborane or N2 gas during growth (click here for STM and SEM images of carbon-based materials grown in our lab). A unique feature of the system is that films can be transferred after growth to the UHV STM system using linear translators without contaminating the films by exposure to air. The UHV STM chamber has an Auger spectroscopy system, low-energy electron diffraction (LEED) system, residual gas analyzer (RGA), ion gun system, electron-beam evaporator and leak valves. In addition, the UHV chamber has a microchannel plate detector and phosphor screen to measure the field-emission (FE) I-V curves and site densities. The sp3 and sp2 carbon content of the films is characterized in situ using a Raman spectroscopy system that is set up next to the growth chamber. The laboratory has a second hot-tungsten filament CVD system, microwave plasma CVD system and atomic force microscopy system.
In our laboratory, we have recently studied the electronic properties of carbon nanotubes using STM,1 and the FE properties of diamond-coated molybdenum (Mo) microtips.2 We have studied CVD grown epitaxial diamond (100)3, (111)4 and (110)5 films, and cesium (Cs) adsorbates on diamond (100) films6 using atomic resolution UHV STM. We have also studied the structural properties of porous silicon using Raman spectroscopy.7 We are currently studying the FE properties of carbon nanotubes and diamond films, as well as the growth and etching of epitaxial diamond films at the atomic scale.8
We have several pages of images related to our research. Feel free to browse around. To see:
