In
this letter, we demonstrate the formation of unique Ga/GaAs/Si nanowire
heterostructures, which were successfully implemented in nanoscale
light-emitting devices with visible room temperature electroluminescence.
Based on our recent approach for the integration of InAs/Si heterostructures
into Si nanowires by ion implantation and flash lamp annealing, we
developed a routine that has proven to be suitable for the monolithic
integration of GaAs nanocrystallite segments into the core of silicon
nanowires. The formation of a Ga segment adjacent to longer GaAs nanocrystallites
resulted in Schottky-diode-like I/V characteristics with distinct electroluminescence originating from
the GaAs nanocrystallite for the nanowire device operated in the reverse
breakdown regime. The observed electroluminescence was ascribed to
radiative band-to-band recombinations resulting in distinct emission
peaks and a low contribution due to intraband transition, which were
also observed under forward bias. Simulations of the obtained nanowire
heterostructure confirmed the proposed impact ionization process responsible
for hot carrier luminescence. This approach may enable a new route
for on-chip photonic devices used for light emission or detection
purposes.