Some Aspects of Phosphorus Diffusion in Germanium in In0,01Ga0,99As / In0,56Ga0,44P / Ge Heterostructures

Abstract

The results of experimental and theoretical researches of phosphorus distribution in the first cascade of a multi cascade solar cell based on nanoscale structures AIIIBV / Ge are presented. Secondary ion mass spectroscopy has been applied to obtain profiles of phosphorus and gallium in In0.01Ga0.99As / In0.56Ga0.44P / Ge heterostructure. In the germanium surface there is a thin layer of about 26 nm, in which the gallium concentration exceeds the concentration of phosphorus. Therefore a nanoscale p-n junction forms that does not have a significant impact on the solar cells performance at room temperature. Phosphorus diffusion is much slower in this area than in area with electronic conductivity. The main p-n junction is formed at a distance of 130-150 nm from the surface of the germanium. Diffusivity of gallium (DGa = 1,4×10 – 15 cm2/s) is markedly higher than described in a literature. Diffusivity of P increase from DP = 3×10-15 cm2/s on the boundary of the heterostructure In0, 49Ga0, 51P to DP = 5,2×10 – 14 cm2/s in n-type Ge. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/33648