Breakdown of Impurity States of As and Sb in Germanium at Uniaxial Compression

Strain-Induced MI Transition in n-Si and n-Ge: Physical Mechanisms and Transport Phenomena

“…Therefore, in n-Si an increase of the electron effective mass at increasing uniaxial pressure X || [111] due to the strain-induced non-parabolicity of the D 1 -valleys [8], determines the physical mechanism of the MIT in high strained degenerative crystals [9]. In germanium, a substantial increase of the electron effective mass due to L 1 -D 1 inversion of the conduction band minima [10] also leads to strain-induced MIT under the condition X || [001] [9]. In the region of the MIT, the measurements were performed on temperature dependences of the crystal resistivity at various pressure (Fig.…”

“…An essential decrease of free electrons concentration due to their localization in region of strain-induced MIT gives rise to an observable decrease of the crystal dielectric constant [2], and leads to more effective localization of electrons on the impurity atoms. In germanium, a substantial increase of the electron effective mass due to L 1 -D 1 inversion of the conduction band minima [10] also leads to strain-induced MIT under the condition X || [001] [9]. In germanium, a substantial increase of the electron effective mass due to L 1 -D 1 inversion of the conduction band minima [10] also leads to strain-induced MIT under the condition X || [001] [9].…”

Calculation of the Ground-State Ionization Energy for Shallow Donors in n-Ge Single Crystals within the ∆1-Model for the Conduction Band

“…The dielectric permittivity for germanium, = 16, is well known [25]. In work [26], by analyzing the dependences of the impact ionization field on the uniaxial pressure along the crystallographic direction [100] for -Ge single crystals doped with Sb and As impurities to the concentration = = 1.8 × 10 14 cm −3 , the ionization energies of ground states for those impurities were determined provided the ( 1 − Δ 1 )-type inversion of the absolute minimum. On the basis of the method used in work [26], the authors of work [27] found the ionization energy for the ground state of P impurity with the concentration = = 1.15 × 10 14 cm −3 associated with Δ 1 -valleys.…”

“…In Table, the calculation results for the ionization energy of shallow-donor ground states in -Ge single crystals taking and not taking the chemical shift for those impurities into account are quoted. In order to compare the theoretical results obtained in this work with the experimental data of works [26,27], the calculations were executed for the concentrations of Sb, P, and As impurities that were used in those works. The results of calculations testify that, when changing from the 1 -model to the Δ 1 -one for the conduction band in -Ge single crystals, the ionization energies of ground states of the Sb, P, and As Ionization energies for the ground states of shallow donors in -Ge associated with Δ 1 -valleys impurities essentially increase.…”

Metal‐Insulator Transition in Degenerately Doped Si and Ge under High Uniaxial Pressure

“…In n-Ge very high uniaxial pressure ( X > 2.1 GPa) along the [OOl] direction results in a Ll-Al inversion of conduction band minima [4]. The L1-Al inversion causes a remarkable increase of the shallow donor ionization energy [5] due to major changes in band minima parameters. In degenerately doped Si and Ge these mechanisms can lead to a transition from a metallic-type to an activated electrical conductivity.…”