The wavelength dependence of drift velocities of photogenerated electrons in CdTe

The drift velocity of photo-generated electrons in CdTe by lasers with wavelengths of 532, 355, and 266 nm is studied by the Monte Carlo method. The effects of laser wavelengths on the electron drift velocity are systematically investigated under various laser fluxes, doping densities, and temperatures. It is found that the drift velocity as a function of electric field $${v}_{\mathrm{d}}(E)$$ v d ( E ) has a close relationship with the laser wavelengths: the electron drift velocity in CdTe becomes larger when a longer photoexcitation wavelength is used. On the other hand, the doping effect, as well as the effect of the laser energy flux, on the $${v}_{\mathrm{d}}(E)$$ v d ( E ) dependence demonstrates different characteristics for different laser wavelengths. The difference in electron drift velocity caused by the various wavelengths reduces with increasing temperatures. In the case of a low laser energy flux, doping in CdTe plays a remarkable role in $${v}_{\mathrm{d}}(E)$$ v d ( E ) relations. These new results are helpful in understanding the microscopic mechanism of relaxation processes of photo-excited carriers and applications of CdTe-based optoelectronic devices. Graphical abstract