Changes in the electrophysical and photoelectrical properties of epitaxial films of Hg1−xCdxTe (x ≈ 0.2) due to laser annealing are studied. Experimental fits for the dependence of the resistance of the film to the energy density of the laser pulse, to the time, as well as to the temperature are obtained before and after laser annealing. Further, changes in the lifetime of minority nonequilibrium carriers of charge and the spectral dependence of the photoconductivity because of laser annealing are shown. Experimental results are interpreted on the basis of the two cluster model for electro- and photoconductivity.
Elucidating the decay mechanisms of photoexcited charge carriers is key to improving the efficiency of solar cells based on organo-lead halide perovskites.
When a solution of microtubule protein is changed from non-polymerising to polymerising conditions (e.g. by temperature jump or mixing with GTP) there is a series of structural transitions preceding microtubule growth. These have been detected by time-resolved X-ray scattering using synchrotron radiation, and they may be classified into pre-nucleation and nucleation events. X-ray patterns are good indicators for the average behavior of the particles in solution, but they are difficult to interpret unless additional information on their structure is available. We therefore studied the assembly process by electron microscopy under conditions approaching those of the X-ray experiment. There are two difficulties in the EM approach: One is that the particles important for assembly are usually small and not very regular and therefore tend to be overlooked. Secondly EM specimens require low concentrations which favor disassembly of the particles one wants to observe since there is a dynamic equilibrium between polymers and subunits.