Extending the detection range of the Raman and photoluminescence spectroscopy setup using the MAPEX funding
Raman and photoluminescence spectroscopy is an established technique for spectroscopy of all kind of materials (solid state materials, liquids, gases, inorganic and organic) using laser excitation in the UV-VIS-NIR spectral range.
The upgrade includes: Installation of a new InGaAs array detector, a 1064 nm laser diode and a long-pass edge optical filter for Raman and photoluminescence spectroscopy in the infrared spectral range up to 1600 nm.
Key benefits: So far, the PL spectral analysis and imaging in the Horiba LabRAM Evolution system was limited to wavelengths up to 1000 nm. However, many materials are optically active in the short-wavelength infrared (SWIR) spectral range above 1000 nm such as Si, InN, InGaN (with a high In content), InGaAs and several 2D materials (e.g. MoTe2, WTe2). To get more detailed spectral and spatio-spatial information of such materials, PL spectroscopy and imaging beyond 1000 nm is needed.
Raman spectroscopy and imaging in the SWIR spectral range is also of interest. Some materials show bright PL or fluoresence in the UV-VIS-NIR spectral range which outshines the Raman signal or is degraded by the irradiation with shorter wavelength lasers, so that Raman spectroscopy and imaging is only possible using a SWIR laser and thus detection in the SWIR spectral range.
Features: The Horiba LabRAM Evolution system is used for Raman, photoluminescence and time-resolved spectroscopy of all kind of materials. The detection range is 200 to 1600 nm (UV-VIS-NIR) using a combination of a CCD and an InGaAs array detector. A Princeton Instruments Spectrometer and a Hamamatsu Streak-Scope enable time-resolved measurements with a detection range up to 1000 nm. Laser excitation for Raman and PL spectroscopy is possible with 325 nm, 442 nm, 633 nm, 785 nm and 1064 nm. For PL spectroscopy only, additional lasers are available at 260 nm, 406 nm and 520 nm. The laser wavelengths at 260 and 520 nm are pulsed laser sources suitable for time-resolved spectroscopy. The system is equipped with a high spatial resolution sample stage covering a range of 7 cm x 7 cm for Raman and photoluminescence mapping. A cryostat is available for low temperature measurements down to 4 K. A mass flow controlled gas flow chamber allows measurements of samples in non-toxic gas environments.
Applied by:
Dr. Christian Tessarek
(Solid State Materials – Institute of Solid State Physics)
