Optimization and characterization of a differential photopyroelectric spectrometer

A differential photopyroelectric (P 2 E) spectrometer using thin pyroelectric PVDF film, with real-time spectrum normalization measurement capability has been developed and characterized. The spectrometer is able to perform measurements as a function of wavelength (limited by the Xe lamp spectrum: 280-1960 nm) and modulation frequency (0.1-600 Hz). The authors describe the abilities and advantages of the photopyroelectric spectrometer over other photothermal spectroscopic instrumentation, and draw attention to different sources of possible experimental errors. Several experiments have been performed as a function of wavelength and/or modulation frequency in order to calibrate, characterize and optimize the working conditions of the photopyroelectric spectrometer. Some further measurements on c-Si have been performed in order to show the instrumentation capabilities. The present differential photopyroelectric spectroscopic technique seems to be very promising toward the characterization of semiconductor thin films and devices.