Modulated photoluminescence spectroscopy with a step-scan Fourier transform infrared spectrometer

Fourier transform infrared (FTIR) spectrometer is a powerful tool for studying the photoluminescence (PL) properties of semiconductors, due to its well-known multiplexing and throughput advantages. However, it suffers from internal He-Ne laser disturbance in near-infrared and/or environmental background thermal emission in mid- and far-infrared spectral regions. In this work, a modulated PL technique is developed based on step-scan (SS)-FTIR spectrometer. Theoretical analysis is conducted, and applications of the technique are given as examples in the PL study of mid-infrared HgCdTe thin films and near-infrared GaInP/AlGaInP multiple quantum wells, respectively. The results indicate that the He-Ne laser and/or thermal emission disturbance can be reduced at least 1/1000 and/or even 1/10 000, respectively, by the modulated SS-FTIR PL technique, and hence a rather smooth PL spectrum can be obtained even under room temperature for HgCdTe thin films. A brief comparison is given of this technique with previously reported phase-sensitive modulation methods based on conventional rapid-scan (RS)-FTIR spectrometer, and the advantages of this technique over the former RS-FTIR-based ones are emphasized.