Modeling and Optimization of Refracting-Facet Spin-Photodiodes Based on Ferromagnetic Metal-Insulator-Semiconductor Tunnel Junctions

A model for lateral-type refracting-facet spin-photodiodes based on ferromagnetic metal-insulator-semiconductor (FM-I-S) junctions is described. The model utilizes spin and charge drift-diffusion equations and spin-dependent tunneling equations which are simultaneously solved numerically in order to obtain a self-consistent solution. The model is used to analyze and optimize the refracting-facet spin-photodiode structure. The relation between the active layer thickness and the effective lifetime of photo-generated electrons is investigated. Results show that the optimum active layer thickness depends on both effective lifetimes of photo-generated electrons and spins. The influence of empty density-of-state of ferromangetic metals is also explored.