Quantum interference in ultra-doped n-type Ge via millisecond flash lamp annealing: structural and electron transport properties

The electron transport characteristics of n-type germanium (Ge) thin films have been widely studied in order to elucidate the underlying mechanisms that govern the performance of Ge-based materials at low temperatures. In this work, ultra-doped n-type Ge layer with phosphorus (P) fluence of 5.4 × 1014 cm-2 has been prepared by ion implantation followed by millisecond-range flash lamp annealing (ms-FLA). The structural and charge transport properties of the FLA-treated ultra-doped Ge:P thin film have been systematically investigated. The resulting material exhibits a high recrystallization quality and a sheet carrier concentration surpassing 5 × 1014 cm-2, which corresponds to an electrical activation yield beyond 90%. Moreover, the low-temperature magnetoresistance measurements, analyzed via the Hikami-Larkin-Nagaoka model, reveal a phase coherence length of around 75 nm, which exhibits a power-law decay with increasing temperature. This work suggests potential pathways toward novel design paradigms for future magneto-electronic devices using Ge-based materials.