Patent ID: 8274096

Claim:
A semiconductor device comprising: at least one p-n junction including a p-type material, an n-type material, and a depletion region, the at least one p-n junction being configured to generate bulk photocurrent in response to incident light, the at least one p-n junction being characterized by a conduction band energy level, a valence band energy level and a surface Fermi energy level, the surface Fermi energy level being pinned either near or above the conduction band energy level or near or below the valence band energy level; and a unipolar barrier structure disposed in a predetermined region within the at least one p-n junction, the unipolar barrier being configured to raise the conduction band energy level if the surface Fermi energy level is pinned near or above the conduction band energy level or lower the valence band energy level if the surface Fermi energy level is pinned near or below the valence band energy level such that the unipolar barrier is configured to propagate the bulk photocurrent and substantially block surface leakage current, the at least one p-n junction and the unipolar barrier being integrally formed.