An all optical approach for comprehensive in-operando analysis of radiative and nonradiative recombination processes in GaAs double heterostructures

Abstract

We demonstrate an all optical approach that can surprisingly offer the possibility of yielding much more information than one would expect, pertinent to the carrier recombination dynamics via both radiative and nonradiative processes when only one dominant deep defect level is present in a semiconductor material. By applying a band-defect state coupling model that explicitly treats the inter-band radiative recombination and Shockley–Read–Hall (SRH) recombination via the deep defect states on an equal footing for any defect center occupation fraction, and analyzing photoluminescence (PL) as a function of excitation density over a wide range of the excitation density (e.g., 5–6 orders in magnitude), in conjunction with Raman measurements of the LO-phonon plasmon (LOPP) coupled mode, nearly all of the key parameters relevant to the recombination processes can be obtained. They include internal quantum efficiency (IQE), minority and majority carrier density, inter-band radiative recombination rate (Wr), minority carrier nonradiative recombination rate (Wnr), defect center occupation fraction (f), defect center density (Nt), and minority and majority carrier capture cross-sections (σt and σtM). While some of this information is thought to be obtainable optically, such as IQE and the Wr/Wnr ratio, most of the other parameters are generally considered to be attainable only through electrical techniques, such as current-voltage (I-V) characteristics and deep level transient spectroscopy (DLTS). Following a procedure developed herein, this approach has been successfully applied to three GaAs double-heterostructures that exhibit two distinctly different nonradiative recombination characteristics. The method greatly enhances the usefulness of the simple PL technique to an unprecedented level, facilitating comprehensive material and device characterization without the need for any device processing.

Impact of dopant-induced band tails on optical spectra, charge carrier transport, and dynamics in single-crystal CdTe

“…2 ), we calculated temperature dependencies of diffusion length in the samples to evaluate the impact of As doping ( L D = ( τ × µkT / e ) 1/2 ). It must be noted, that diffusion length and all carrier recombination parameters are carrier density dependent 42 , thus determination of electron and hole diffusion lengths is a complex and ambiguous task. As observed, As doping strongly reduces diffusion length due to lifetime drop in comparison to high-resistivity U sample (Fig.…”

Sub-Picosecond Carrier Dynamics Explored using Automated High-Throughput Studies of Doping Inhomogeneity within a Bayesian Framework

“…where Bp, Cp 2 , 4S/d are radiative, Auger, and surface recombination rates. The material parameters are: B -the radiative recombination rate estimated between 10 −9 to 10 −10 cm 3 /s, 52,53 C -the Auger rate estimated between 10 −26 to 10 −31 cm 6 /s, 54,55 and S -the surface recombination velocity estimated to be between 5-13×10 5 cm/s for diameter between 100-300 nm. 12, 33,34 The experimental scaling factor α is related to the conditions such as laser power and spot size, microscope collection efficiency, and spectrometer quantum efficiency.…”

Sub‐Picosecond Carrier Dynamics Explored using Automated High‐Throughput Studies of Doping Inhomogeneity within a Bayesian Framework

“…where Bp, Cp 2 , 4S/d are radiative, Auger, and surface recombination rates. The material parameters are: B -the radiative recombination rate estimated between 10 -9 and 10 -10 cm 3 s -1 , [57,58] C -the Auger rate estimated between 10 -26 and 10 -31 cm 6 s -1 , [59,60] and S -the surface recombination velocity estimated to be between 5 and 13 × 10 5 cm s -1 for dia meter between 100 and 300 nm. [12,33,34] The experimental scaling factor α is related to the conditions such as laser power and spot size, microscope collection efficiency, and spectrometer quantum efficiency.…”