DOI: 

Optoelektron. napìvprovìd. teh. 61, 132-142 (2026)

P.О. Gentsar, М.А. Мynaylo. 

THE OPTICAL SPECTROSCOPY OF THE HEAVILY DOPED n-Ge1-xSix SOLID SOLUTION

In this work, in order to obtain data on the energy band structure, as well as to understand the physical processes, mechanisms, and nature of the formation of electronic and optical phenomena on the surface and in the near-surface layer, heavily doped polycrystalline n-Ge1-xSix solid solutions obtained from powders were studied. These were doped to electron concentrations of N = 1025 m-3 ÷ 1026 m-3 with a solution composition x in the range 0.6 ≤ x ≤ 0.8. It was taken into account that the minimum of the conduction band of the studied samples is located in the Δ direction of the Brillouin zone.

The mechanisms of broadening of optical spectra of heavily doped n-Ge1-xSix solid solution were analyzed. The effective relaxation time of free charge carriers τ was estimated. The parameters of the energy band structure were obtained: effective optical mass of electrons , transverse mass of electrons , longitudinal mass of electrons m║, effective mass of the density of states and parameters of the space charge region of the studied crystals (optical transition energy E1 ();  surface electric field Fs; electro-optical energy ℏθ; phenomenological broadening parameter Г; classical enrichment layer thickness; characteristic parameter λFK for the Franz-Keldysh effect with a length that determines the oscillation length of the wave function of a quantum-mechanical particle with a reduced effective mass μ in a uniform electric field Fs; de Broglie wavelength λD-B of a quantum-mechanical particle with an effective mass density of states  ; electromagnetic wave penetration length d in the energy range 2.5 eV ÷ 3.8 eV).

Keywords: n-Ge1-xSix, mechanisms of broadening of optical spectra, effective relaxation time of free charge carriers, reflection spectra, electrical reflection spectra.