Top-to-Bottom Local Epitaxial Growth of the Two-Dimensional Antimony Telluride Film by Atomic Layer Deposition Using Sacrificial Germanium Telluride

This study introduces a novel atomic layer deposition (ALD) method for growing a uniform and ultrathin two-dimensional Sb2Te3 crystalline film. The method utilizes an amorphous GeTe film as a sacrificial buffer layer, where Ge atoms serve as anchoring sites even on the inactive van der Waals surface. The Sb atoms replace the Ge atoms to form the Sb2Te3 film with the growth type changed from island to the desired layer-by-layer. The conformal Sb2Te3 film growth is self-terminated when the diffused Sb atoms from the growing film surface replace all of the Ge atoms. This process enables precise film thickness control even on extreme geometric substrates. This unique ALD method, referred to as top-to-bottom local epitaxial growth, offers promising potential for depositing uniform two-dimensional metal dichalcogenides for diverse applications.