"A case study in surface science and quantum computing."
Dr Neil Curson
Centre for Quantum Computer Technology
School of Physics
University of New South Wales
Sydney, Australia
neil.curson@unsw.edu.au
Location: NPL 201 2:00pm.
ABSTRACT: Scanning tunneling microscopy (STM), supported by first principles density functional theory (DFT) calculations, is used to characterise the species formed on the Si(001) surface after PH3 dosing and to follow the evolution of the adsorption system as a function of time and temperature. After dosing with PH3, the dominant species on the Si(001) surface are the PH2 + H and PH + H2 and hemihydrides, with other species such as P + 3H and isolated ‘end-bridge bonded’ P atoms less prevalent. Dissociation reactions can be followed directly in sequences of STM images. For example the reaction sequence PH2 + H --> PH + H2 ---> P + 3H is routinely observed at room temperature (RT), on the timescale of minutes, with the reaction products remaining bound to the surface. The reverse reactions are never seen. In addition we demonstrate the positioning of individual P atoms into substitutional Si(001) surface lattice sites with 1 nm accuracy, using STM to pattern a monolayer hydrogen resist.
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