Влияние глубоких уровней дислокаций в гетероэпитаксиальных InGaAs/GaAs и GaAsSb/GaAs p-i-n-структурах на время релаксации неравновесных носителей

Abstract

AbstractThe results of an experimental study of the capacitance–voltage ( C – V ) characteristics and deep-level transient spectroscopy (DLTS) spectra of p ^+– p ^0– i – n ^0 homostructures based on undoped dislocationfree GaAs layers and InGaAs/GaAs and GaAsSb/GaAs heterostructures with homogeneous networks of misfit dislocations, all grown by liquid-phase epitaxy (LPE), are presented. Deep-level acceptor defects identified as HL 2 and HL 5 are found in the epitaxial p ^0 and n ^0 layers of the GaAs-based structure. The electron and hole dislocation-related deep levels, designated as, respectively, ED 1 and HD 3, are detected in InGaAs/GaAs and GaAsSb/GaAs heterostructures. The following hole trap parameters: thermal activation energies ( E _ t ), capture cross sections (σ_ p ), and concentrations ( N _ t ) are calculated from the Arrhenius dependences to be E _ t = 845 meV, σ _ p = 1.33 × 10^–12 cm^2, N _ t = 3.80 × 10^14 cm^–3 for InGaAs/GaAs and E _ t = 848 meV, σ _ p = 2.73 × 10^–12 cm^2, N _ t = 2.40 × 10^14 cm^–3 for GaAsSb/GaAs heterostructures. The concentration relaxation times of nonequilibrium carriers are estimated for the case in which dislocation-related deep acceptor traps are involved in this process. These are 2 × 10^–10 s and 1.5 × 10^–10 s for, respectively, the InGaAs/GaAs and GaAsSb/GaAs heterostructures and 1.6 × 10^–6 s for the GaAs homostructures.