Significant enhancement of photoresponsivity in As-doped n-BaSi2 epitaxial films by atomic hydrogen passivation

We grew 500-nm-thick lightly As-doped n-BaSi2 epitaxial films at 600 degrees C by molecular beam epitaxy, and supplied atomic H in durations (t(BaSi:H)) of 0-30 min, followed by capping with a 3-nm-thick amorphous Si layer at 180 degrees C. The photoresponsivity of the BaSi2 films was enhanced by approximately five times by As doping. Deep-level transient spectroscopy measurement revealed the disappearance of two previously reported electron traps. The photoresponsivity was further enhanced by approximately six times after H supply. It reached a maximum at t(BaSi:H) = 1-10 min, owing to the reduction of defects.