Effect of dislocation-related deep levels in heteroepitaxial InGaAs/GaAs and GaAsSb/GaAs $p$–$i$–$n$ structures on the relaxation time of nonequilibrium carriers

The 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 $(\sigma_p)$, and concentrations $(N_t)$ are calculated from the Arrhenius dependences to be $E_t$ = 845 meV, $\sigma_p$ = 1.33 $\times$ 10$^{-12}$ cm$^2$, $N_t$ = 3.80 $\times$ 10$^{14}$ cm$^{-3}$ for InGaAs/GaAs and $E_t$ = 848 meV, $\sigma_p$ = 2.73 $\times$ 10$^{-12}$ cm$^2$, $N_t$ = 2.40 $\times$ 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 $\times$ 10$^{-10}$ s and 1.5 $\times$ 10$^{-10}$ s for, respectively, the InGaAs/GaAs and GaAsSb/GaAs heterostructures and 1.6 $\times$ 10$^{-6}$ s for the GaAs homostructures.