High mobility single-crystalline-like germanium thin films on flexible, inexpensive substrates

Single-crystalline-like epitaxial germanium thin films with hall mobility values as high as 833cm2/Vs have been demonstrated on inexpensive polycrystalline metallic substrates. The dependence of mobility of p-type and n-type germanium films on the deposition temperature has been examined and correlated to microstructural changes. The importance of crystallographic orientation of Ge to achieve these high mobility values has been verified. The mobilities of the epitaxial germanium films on the film thickness for p-type and n-type films with multi-layer architecture with different epitaxial intermediate layers have been investigated. Results show that the increased mobility with increasing germanium film thickness is not just due to crystallographic texture improvement, but could also be a result of decreasing defect density. ► Single-crystalline-like films of p-Ge and n-Ge on flexible, inexpensive substrates ► p-Ge and n-Ge films with mobility of 833 and 343cm2/Vs on these substrates ► Ge grain size, (400) peak intensity, and hall mobility increase rapidly above 630°C. ► Hole mobility increases and defect density decreases with increasing Ge thickness.