The aim of the Working Group is to develop practical II-VI semiconductor visible and UV lasers for advances in information technology.
The programme links together three laboratories (Heriot-Watt University, Würzburg University and the CNRS LPSES) which have molecular beam epitaxial growth, assessment, spectroscopy and fabrication expertise with three specific goals:
- demonstrate a CW room-temperature blue diode laser
- address the device lifetime problems of both room temperature pulsed and CW lasers
- demonstrate a near UV (350 nm) pulsed laser at low temperatures.
The approaches involve increasing the p-doping levels in ZnSe based materials, improving the contacting to these p-layers, comparing lattice matched and strained laser structures, fabricating ridge wave guide structures, developing the growth and doping of CdZnSSe and MgZnSSe quaternary systems, using substrates other than GaAs as well as understanding the details of the lasing mechanism in II-VI devices where excitonic recombination dominates.
The Working Group's expertise ranges from fundamental studies of semiconductor materials, including growth and spectroscopy, to device fabrication technology and laser diode assessment. Each member of the Group has access to a wide range of research facilities either within their department or through well established collaborations with university and industrial laboratories. The regular exchange of staff between the members of the Working Group will provide the close contact necessary for the continuity of the programme and an annual workshop will allow the progress of each group to be formally reported. Representatives from other European research groups working in the area will be invited to discuss special topics and the Working Group will organise an International Workshop on blue laser diodes.
The research towards blue and UV diode lasers will be addressed in the longer term (5 years) as the development of improved materials, contacts and structures takes the devices from the basic research stage to a prototype product development stage. The ability to fabricate II-VI semiconductor lasers has been demonstrated but considerable technological advances will be necessary before practical devices are available. We see this Basic Research Working Group as leading to a Project that would involve major IT companies.