Blocking contact p++-p+-p in silicon IR photoreceivers with conductivity of the p-type

A new conception is suggested for the blocking of dark conduction in semiconductors with one conduction type containing several one-type transitions of the type p++-p-p+-p++. The blocking is explained by the presence of a potential barrier in the region of a p+-p transition located in the crystal at depth 10-15 μm from one of the contacts. External electric field is screened by the space charge region of this transition, and charge transfer along the valent zone is absent without structure illumination.