Silver-induced layer exchange for polycrystalline germanium on a flexible plastic substrate

Abstract

Crystalline Ge was directly achieved on a flexible plastic by layer exchange between Ag and amorphous Ge layers. The key factor for the layer exchange was limiting the diffusion of Ag to Ge by lowering the growth temperature (250 °C) and controlling the condition of an interlayer (1-nm-thick SiO2) between Ag and Ge. The layer exchange using Ag provided much faster nucleation and lateral growth rates of Ge compared with the conventional solid-phase crystallization and Al-induced layer exchange. A principle to determine the materials for layer exchange is proposed from the perspective of the diffusion and solubility of metals and semiconductors.