Photodetectors on the basis of Ge/Si(001) heterostructures grown by the hot-wire CVD technique

The fabrication of photodetectors for the wavelength range of communications $\lambda$ = 1.3–1.55 $\mu$m on the basis of Ge/Si(001) heterostructures with thick ($\sim$ 0.5 $\mu$m) Ge layers grown by the hot-wire technique at reduced growth temperatures (350$^\circ$C) is reported. The single-crystal Ga layers are distinguished by a low density of threading dislocations ($\sim$ 10$^5$ cm$^{-2}$). The photodetectors exhibit a rather high quantum efficiency ($\sim$ 0.05 at $\lambda$ = 1.5 $\mu$m and 300 K) at moderate reverse saturation current densities ($\sim$ 10$^{-2}$ A cm$^{-2}$). Thus, it is shown that the hot-wire technique offers promise for the formation of integrated photodetectors for the wavelength range of communications, especially in the case of limitations on the conditions of heat treatments.