Abstract:
A Czerny Mount double monochromator is used to measure Raman scattered radiation
near 90" from a crystalline, Silicon sample. Incident light is provided by a mixed gas
Kr-Ar laser, operating at 5145 A. The double monochromator is calibrated to true
wavelength by comparison of Kr and Ar emission Une positions (A) to grating position
(A) display [1]. The relationship was found to be hnear and can be described by,
y = 1.219873a; - 1209.32, (1)
where y is true wavelength (A) and xis grating position display (A). The Raman emission
spectra are collected via C"*""*" encoded software, which displays a mV signal from a
Photodetector and allows stepping control of the gratings via an A/D interface. [2]
The software collection parameters, detector temperature and optics are optimised
to yield the best quality spectra. The inclusion of a cryostat allows for temperatmre
dependent capabihty ranging from 4 K to w 350 K.
Silicon Stokes temperatm-e dependent Raman spectra, generally show agreement with
Uterature results [3] in their frequency haxdening, FWHM reduction and intensity increase
as temperature is reduced. Tests reveal that a re-alignment of the double monochromator
is necessary before spectral resolution can approach literature standard. This has not
yet been carried out due to time constraints.
