For high-speed data processing, the synergy of photons and electrons requires their absorption and conversion characteristics to be suited for near-infrared optical communication. Here, we report on the formation of high-quality germanium on oxide for photodetectors as well as its characteristic measurements. The Ge film was made by using the rapid-melting-growth technique, and the quality was verified by Raman spectroscopy and standard electron microscopy. The high-quality Ge was integrated with P-type and N-type silicon pillars to form a PIN photodetector. The electrical measurement identified its responsivity to the near-infrared spectrum. This work demonstrated that a high-quality Ge film can be obtained using a metal-oxide-semiconductor field-effect transistor compatible process with good photoelectric conversion efficiency and responsivity.