Two large area （φ1.6mm） Ge photo-detectors with a groove-mesa structure have been-fabricated adopting Sb-doped N typegermanium crystal with resistivities of 0.35Ω-cm and 6Ω-cm as the substrate material

using ion-implantations of B

+

or Be

+

for forming a p

+

region. The measured photoelectric characteristics indicate that

the spectral response does not depend on the sort of implanted ions and material resistivity when these Ge-PDs are applied at a bias voltage of nearly zero volt

but I-V characteristics and light response （Re） depend on material resistivity

junction depth and the sort of implanted ions.