The development of new techniques to control and manipulate free surfaces and interface barriers related to the improvement of semiconductor quantum well laser operation was considered. In particular, surface passivation of atomic scale defects on the laser facet using ultra-thin Si layers deposited at 280C was analyzed. The local passivation mechanism was observed directly by using a combination of surface science techniques, mainly scanning tunnelling microscopy/spectroscopy. The Si was found to selectively bond to defects and return the corresponding electronic properties to the flat band condition. Secondly, heterojunction modification to enhance carrier confinement within the active region of the device was considered using multi-quantum barriers based on theoretical modelling and experimental verification. Limitations of the techniques were also addressed. The use of scanning tunnelling microscopy and scanning tunnelling spectroscopy to investigate interface modification on the nm scale was highlighted.

Engineering and Investigating the Control of Semiconductor Surfaces and Interfaces. S.P.Wilks: Journal of Physics D, 2002, 35[4], R77-90