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Cambridge Centre for Gallium Nitride


The Cambridge time-resolved cathodoluminescence (TRCL) scanning electron microscope (SEM) is managed as a facility by Professor Rachel Oliver and Dr Gunnar Kusch, of the Cambridge Centre for Gallium Nitride. 

The system is an Allalin 4027 Chronos from Attolight, designed to work both in continuous (CW) and time-resolved (TR) cathodoluminescence modes. In continuous mode, it produces high resolution cathodoluminescence maps with low signal to noise ratios. In time-resolved mode it generates spectrally resolved lifetime maps. 

Through a combination of a high brightness electron gun for increased probe currents and very efficient light collection optics, the system provides high signal intensities and hence fast hyper-spectral imaging of luminescence. It is possible to switch on-the-fly from continuous to picosecond electron emission. The system includes a spectrometer and a CCD camera for hyperspectral mapping in the ultraviolet-to-visible spectral range; a streak camera for ultrafast multichannel picosecond time-resolved detection; and an ultra-stable Helium cryogenic nano-positioning stage with six degrees of freedom. For samples emitting in the infra-red, CW detection is achieved using an InGaAs linear array, whilst an InGaAs/InP APD is used for time-correlated single photon counting (TCSPC) measurements to achieve time resolution. The system also features an electron beam induced current (EBIC) mode that is compatible with the low temperature cryostat.

The system was funded by an EPSRC strategic equipment grant (EP/R025193/1), and was delivered in March 2019 and commissioned in September 2019. It is possible to access the system from outside Cambridge, but priority will be given to users whose proposed experiments utilise the advanced capabilities of the system, and would not be possible on a more standard SEM or CL setup. 


How to access the system?

To apply for access to the system, users from inside or outside Cambridge should initially fill in the following form and send it by email to Prof Rachel Oliver on [Word]/[PDF].

Prior to accessing the TRCL Facility we request that all users and their supervisors read and sign the acknowledgements and publications policy: [Word]/[PDF].