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Interband magneto-optical studies are reported on strained and unstrained films of PbTe grown on BaF2, NaCl and PbTe substrates. By a careful orientational study of the magneto-absorption of these films it has been possible to deduce an accurate set of band parameters for PbTe, using the six-band Mitchell-Wallis k.p model. It is demonstrated that the inbuilt strain in the layers is an important parameter, which can cause changes in both the bandgap, and the momentum matrix element coupling the L3- 6- and L1+ 6+ bands. Both uniaxial and hydrostatic components of strain are shown to be present, and these are used to deduce the deformation potentials for PbTe. The anisotropy of the conduction and valence bands is shown to be independent of the strain.

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In this study, we investigate the performance of two piezoresistive micro-electro-mechanical system (MEMS)-based silicon cantilever sensors for measuring target analytes (i.e., ultrafine particulate matters). We use two different types of cantilevers with geometric dimensions of 1000 × 170 × 19.5 µm3 and 300 × 100 × 4 µm3, which refer to the 1st and 2nd types of cantilevers, respectively. For the first case, the cantilever is configured to detect the fundamental in-plane bending mode and is actuated using a resistive heater. Similarly, the second type of cantilever sensor is actuated using a meandering resistive heater (bimorph) and is designed for out-of-plane operation. We have successfully employed these two cantilevers to measure and monitor the changes of mass concentration of carbon nanoparticles in air, provided by atomizing suspensions of these nanoparticles into a sealed chamber, ranging from 0 to several tens of µg/m3 and oversize distributions from ~10 nm to ~350 nm. Here, we deploy both types of cantilever sensors and operate them simultaneously with a standard laboratory system (Fast Mobility Particle Sizer, FMPS, TSI 3091) as a reference.