Germanium (Ge) is considered as one of the most promising materials for near infrared (NIR) photodetectors, due to its large absorption coefficient at NIR wavelengths, high carrier mobilities, and process compatibility with silicon (Si) architecture. Focusing on the challenges of Ge NIR photodetectors, in this paper, the progress of Ge materials and technologies for photodetectors in our group was reviewed extensively. Firstly, the preparation process of Si-based Ge materials was introduced, in which high crystal quality Si-based Ge materials were fabricated by a two-step epitaxy method, Ge/Si wafer bonding, and Ge condensation techniques, respectively. Then the n-type doping technology of Ge was studied, in which high n-type doping concentrations and shallow junctions of Ge materials were prepared by two-step annealing (low temperature pre-annealing and excimer laser annealing) for phosphorus-implanted Ge substrate and spin-on doping of phosphorus on Ge substrate, respectively. Finally, the modulation of Schottky barrier height of metal/Ge contacts were studied, and a high-performance Ge Schottky photodetector was prepared by combining ITO transparent electrode and ultra-thin metal film interlayer.