Effect of Dislocation-related Deep Levels in Heteroepitaxial InGaAs/GaAs and GaAsSb/GaAs p–i–n Structures on the Relaxation time of Nonequilibrium Carriers

Abstract

The results of an experimental study of the capacitance–voltage (C–V) characteristics and deep-level transient spectroscopy (DLTS) spectra of p+–p0–i–n0 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 HL2 and HL5 are found in the epitaxial p0 and n0 layers of the GaAs-based structure. The electron and hole dislocation-related deep levels, designated as, respectively, ED1 and HD3, 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 cm2, N t = 3.80 × 1014 cm–3 for InGaAs/GaAs and E t = 848 meV, σ p = 2.73 × 10–12 cm2, N t = 2.40 × 1014 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.