Abstract
Crystalline Ge is superior to Si in the points that the mobility of carriers is higher and the recrystallization temperature is lower. As the energy gap is small, it could be applied to the optical sensor in infrared region. The amorphous thin films, however, have not been applied to the devices because the films involve high density of dangling bonds. To terminate the dangling bonds, the hydrogen atoms are introduced in the films. The hydrogenated amorphous Ge thin films are prepared by glow discharge method, ECR plasma CVD method and reactive sputtering method. Here, we introduce the fundamental properties of hydrogenated amorphous Ge including energy band model, which were obtained so far.
