Welcome to the Nanophotonics home.

Nanophotonics
We use the Stranski-Krastanow (SK) growth mechanism (self-assembly) to grow semiconductor quantum dots and wires. The study on the S-K growth is to create novel quantum nanostructures. For the growth optimization, a commercial scanning tunneling microscope (STM) is attached to a commercial molecular beam epitaxy (MBE) machine through an ultra-high vacuum (UHV) port to study the MBE grown substrates in-situ. The research focuses on the optical properties in nanometer scale, nanophotonics.
Equipments – overview The picture shows the full view of the equipments, MBE growth chamber (in the middle with a growth control computer on the right), STM machine (between the MBE chamber and the control electronics rack) and an optical microscope (far right).
Top view of the all solid-source MBE machine (SVTA – 35N). The picture shows the ten source ports with six of them occupied. The six cells are shown empty and charged with Ga, In and Al for V-element sources, Be and Si (hidden below the flux gauge and the shutter) for dopants, and solid As source. The other four source ports are empty but planned to be phosphide and nitride source ports.	Top view of the imaging station of the scanning tunneling microscope (Omicron STM). The tip is on the left tripod and the sample is at the right of the center.
MBE growth – Shown above is a Reflection High Energy Electron Diffraction (RHEED) pattern. The pattern is from GaAs(001) at 500ºC, with the beam energy at 8.2keV, the beam direction along [1b10] azimuth direction to create 4x periodicity. Note not symmetric. The RHEED pattern is taken after 0.5 micrometer thick buffer layer growth at 580ºC at 0.4 monolayer per second.	An in-situ surface image of GaAs(001)-2x4 reconstruction taken by the above Omicron STM machine. The dimmer rows and one monolayer step is clearly resolved. The left RHEED pattern is from the same surface after the MBE growth.
	Shown left is an in-situ (as-grown) surface image of InGaAs quantum dots grown on a GaAs(001) buffer layer shown above	.
Shown right is a three-dimensional STM image of InGaAs dot-chains on GaAs(001) substrate. The dot-chains were formed through annealing the strained-but-flat epilayers at 460C.
Optical Microscope, Olympus Trinocular BX41 – this optical microscope is used to monitor the etching process of an STM tip and evaluate the tips. The Trinocular option provides us to visualize the etching process in real-time when connected to a projector, which is an excellent training/teaching tool. The picture on the right shows a successfully etched STM tip. It was taken using a digital camera attached to the Trinocular tube of the microscope.	Optical microscope image of the STM tip used to take above STM image of the MBE grown GaAs surfaces.
We are seeking for collaborations related with molecular beam epitaxy (MBE). Please e-mail us if you have an idea/concept, which requires a state-of-the-art MBE machine.
Inquiries 1-435-797-8111 (Tel) 1-435-797-2492 (Fax) mailto:yang@cc.usu.edu