Abstract: Methods of hydrogen atom incorporation and of passivation of grain boundaries of polycrystalline semiconductors use a low temperature, pulsed plasma to incorporate hydrogen atoms into the grain boundaries of polycrystalline semiconductor materials in a controlled manner. A hydrogen-passivated polycrystalline IR detector has hydrogen atoms incorporated into grain boundaries of a polycrystalline Group III-V compound semiconductor detector element and a dark current density characteristic that is lower than the dark current density characteristic of a polycrystalline IR detector without the incorporated hydrogen atoms.