UK Team Develops Novel Spectroscopy Technique
X-ray photoelectron spectroscopy has the potential to become an important technique in compound semiconductor quality control
A novel use of X-ray photoelectron spectroscopy (XPS) is being pioneered by physicists at Lancaster University working with technology firm Kratos Analytical.
XPS has the potential to become an important technique in the development and production quality control of compound semiconductor devices such as VCSELs, according to the researchers.
Manus Hayne from Lancaster University's Department of Physics said: "XPS is used almost exclusively on surfaces as it has an extremely small penetration depth into the material of only a few atomic layers.
"However, by slowly and carefully etching the material in situ in the XPS machine we have shown that the technique can be applied to allow the accurate determination of the elemental composition of compound semiconductor materials with multiple layers of different alloys."
The ability to engineer the electronic and optical properties of compound semiconductors, for example in terms of their alloy composition, and grow multiple layers of different semiconductors on top of each other (heterostructures), is a key part of their success.
Hayne's work with Kratos is an offshoot of his QR-SPLED project, funded through Innovate UK and the Engineering and Physical Sciences Research Council (EPSRC), in the framework of the UK National Quantum Technologies Programme.
The project is assessing the feasibility of mass-producing low-cost, single-photon sources in the form of single-photon light emitting diodes (SPLEDs), by exploiting the unique properties of semiconductor nanostructures called self-assembled quantum rings. It follows on from a recent project in which Hayne and collaborators demonstrated novel quantum-ring VCSELs.
Hayne is a world authority on self-assembled GaSb/GaAs quantum rings and their use in devices such as telecoms-wavelength VCSELs.