Germanium single crystal is germanium crystal with-out large Angle boundary or twin. It is an important semiconductor material with diamond crystal struc-ture. Single crystal germanium is a semiconductor material originally used to make transistors and diodes. In the 1970s, after it was replaced by monocrystalline silicon, germanium turned to infra-red optical applications due to its higher electron and hole mobility than silicon and better perfor-mance than silicon in high-speed switching circuits. Horizontal zone melting is the main method to grow single crystal of germanium used in electronic mate-rials in the past. However, because of the small cross section area of single crystal of germanium, it could not meet the requirements of infrared optics and was eliminated.