Nikolenko A. Photoelectrical properties of multilayer SiGe heterostructures with nanoislands

Experimental results of photoconductivity and photo-EMF spectral dependences investigation of multilayer heterostructures with SiGe nanoislands are represented in the thesis. Theoretical model of SiGe-island/Si-surrounding heterojunction band structure calculation is suggested. The model enables determination of possible optical transition types and their energy estimation. Analysis of Raman scattering spectral dependences and atomic-force microscopy images of the investigated structures was used in order to take into account composition, deformations and sizes of nanoislands. An effect of the applied electric field and thermal annealing of the investigated structures on the shape of photoconductivity spectra are analyzed. Suggested using of SiGe nanoisland layers embedded into the base of p-i-n structure make it possible to increase considerably the photosensitivity in the range of indirect in space interband transitions.