Experiments with PbTe p-n-p-structures
As an experimental test for the proposed concept single period nipi's are realized by a PbTe p-n-p layer scheme.
The p-layers are designed to be buffers at the interface and at the surface with a thickness ranging from 0.5µm to
1µm in order to provide a well defined position of the Fermi level outside the nipi potential. The n-layer are
designed to be non depleted resulting in a layer thickness ranging from 0.2µm to 1µm depending on the doping
level. Selective contacts to the embedded n-layer are realized by diffusion of In into the structure.
The photoconductive measurements are carried out in a two terminal configuration using a constant current source.
The optical excitation is done by a PbEuSe-heterojunction laser diode, operated at a wavelength of lambda approx
4.2µm, which corresponds to photon energies well above the band gap of PbTe in the considered temperature
range.
According to the different cases in the simulations two representative
experimental conditions are choosen in order to compare the results of the experiments and simulations:
For more detailed information