Epitaxial n+-Ge/p+-Si(0 0 1) heterostructures with ultra sharp doping profiles for light emitting diode applications

•Heavily doped n+-Ge:P epitaxial layers (the electron concentration up to 2 · 1019 cm−3) were grown on p+-Si(001) substrates by low-temperature (325 °C) Hot Wire Chemical Vapor Deposition with doping by P from a sublimation solid-phase GaP source.•Abrupt donor and acceptor concentration profiles at the n+-Ge:P/p+-Si(100) interfaces were obtained.•Prototype light emitting diodes (LEDs) were fabricated from the n+-Ge:P/p+-Si(100) heterostructures. Room-temperature electroluminescence at room temperature was observed.•Negative differential resistance was observed in the current–voltage curves of the LEDs at room temperature.