A novel wave-guide Ge:Ga photoconductor

A wave-guide gallium-doped germanium (Ge:Ga) extrinsic photoconductor coupled to a silicon solid-immersion lens was developed. A linear-array configuration was automatically achieved via the fabrication process. The typical distance between the electrodes was designed to be 0.050 mm (/spl sim/2 wavelength/refractive index), which is about one-tenth of that in conventional Ge:Ga photoconductors. The short distance between the electrodes resulted in high responsivity and low noise characteristics.