Effect of ge-dosing profile of exponentially-doped base on the internal quantum efficiency of a SiGe solar cell

Quantum efficiency of a SiGe solar cell has been developed for box, triangular and trapezoidal dosing profiles of Ge in exponentially doped base. The doping dependency of carrier mobility and carrier lifetime, the band-gap narrowing effect due to heavy doping level and velocity saturation effects are considered to deduce the governing differential equation for this model. An elegant exponential approximation technique has been employed to simplify the complicated nature of variable coefficients of the working differential equation. The model results show that the increased Ge-content in the base results in significant improvement in the internal quantum efficiency.