A photoacoustic spectrometer apparatus adapted to enable an observation
and characterisation of non-radiative sub bandgap defects in narrow and
large bandgap materials using photoacoustic spectroscopy techniques, the
apparatus providing for an irradiation of a sample material provided
within a photoacoustic cell and the subsequent detection and processing
of an acoustic signal emitted by the sample, the apparatus comprising a
light source having a polychromatic output substantially in the photonic
energy range 0.5 eV to 6.2 eV, focusing means adapted to couple the
output from the light source onto the sample material, the focusing means
providing for an alignment and focusing of the light emitted from the
light source so as to provide a substantially parallel incident light
onto the sample material, and means for detecting and acquiring the
acoustic signal emitted by the sample in response to the irradiation. A
method of providing an acoustic signal spectrum emitted by a sample
material provided within a photoacoustic cell following irradiation of
the sample by an incident light beam is also provided.