Autosolitons in electron-hole plasma in p-Ge

Abstract

The self-organization of an electron-hole plasma (EHP) heated by an electric field in pure p-Ge samples at T = 77 K has been studied experimentally. The derived current-voltage characteristics (CVCs) and the distributions of the electric field and IR emission of the hot carriers along the samples show that the segments of a steep rise or the S-shaped segments of the CVCs in samples with n-p junctions are related to the formation of longitudinal thermal-diffusion autosolitons (AS‖); as a result, thin (d = 2–20 µm in diameter), melted-through current channels appear. Such AS‖ are formed at high EHP densities (n ≥ 1 × 1016 cm−3), when the electron-hole scattering is dominant, and at electron temperatures Te = (2–4.5)T0 (T0 is the lattice temperature). The saturation segments and the N-shaped segments in the CVCs are attributable to the generation of transverse thermal-diffusion high-field autosolitons (AS⊥) in the form of narrow strata with electric field strengths \(E_{AS_ \bot } \) = 1–20 kV cm−1. High-field AS⊥ are formed at EHP densities n = 5 × 1013−1 × 1016 cm−3, when the electron-phonon scattering is dominant, and at electron temperatures Te ∼ Θ ≥ 5T0 (Θ is the Debye temperature). The generated longitudinal and transverse autosolitons have high temperatures (Te ≥ 1000 K) and reduced carrier densities and can exist simultaneously in different parts of the sample.