Low-temperature crystallization of amorphous silicon and amorphous germanium by soft X-ray irradiation

• This work investigates the crystallization mechanism for soft X-ray irradiation.
• The soft X-ray crystallization depended on the energy band gap and energy level.
• The decrease in the crystallization temperature for Si and Ge films was 100 K.
• This decrement was related to atoms transitioning into a quasi-nucleic phase.

The low-temperature-crystallization effects of soft X-ray irradiation on the structural properties of amorphous Si and amorphous Ge films were investigated. From the differences in crystallization between Si and Ge, it was found that the effects of soft X-ray irradiation on the crystallization strongly depended on the energy band gap and energy level. The crystallization temperatures of the amorphous Si and amorphous Ge films decreased from 953 K to 853 K and 773 K to 663 K, respectively. The decrease in crystallization temperature was also related to atoms transitioning into a quasi-nucleic phase in the films. The ratio of electron excitation and migration effects to thermal effects was controlled using the storage-ring current (photon flux density). Therefore, we believe that low-temperature crystallization can be realized by controlling atomic migration through electron excitation.