Enhanced photoluminescence of heavily doped $n$-Ge/Si(001) layers

The photoluminescence spectra of epitaxial $n^+$-Ge:P/Si(001) structures are studied. The structures are grown by hot-wire chemical vapor deposition and doped with phosphorus to the maximum electron concentration 1 $\times$ 10$^{20}$ cm$^{-3}$ from a source based on thermally decomposed GaP. The effects of the doping level and rapid thermal annealing of $n^+$-Ge:P layers on the photoluminescence spectra are studied. It is demonstrated that the epitaxial $n^+$-Ge:P/Si(001) layers grown by hot-wire chemical vapor deposition are promising for application as active regions of light-emitting optoelectronic devices operating in the near-infrared spectral region.