Abstract:The thermal quenching of the photoluminescence (PL) intensity in Ga(As,Bi)/GaAs heterostructures is studied experimentally and theoretically. We observed an anomalous plateau in the PL thermal quenching at intermediate temperatures under low excitation conditions. Our theoretical analysis based on a well‐approved theoretical approach shows that this peculiar behavior of the temperature‐dependent PL intensity cannot be interpreted assuming a single‐scale monotonously energy‐dependent density of localized states… Show more
“…Shakfa et al . suggest that this results from a two-component LDOS distribution, where at intermediate temperatures the radiative recombination of localised excitons from a deeper distribution of states balances the increasing non-radiative recombination as carriers in shallow states are excited above the mobility edge 50 . Evidence of a the dual-component distribution to the localised states is also observed by Imhof et al ., who show excellent agreement with experimental data using a kinetic Monte Carlo model taking into account exponential and Gaussian distributions on two energy scales to describe the hopping dynamics of carriers amongst the localised states 27 .Figure 4 (a) The thermal quenching of integrated luminescence intensity for varying incident excitation power.…”
Section: Presentation and Discussion Of Resultsmentioning
confidence: 99%
“…The energy scales of the two Gaussian distributions are in good agreement with those extracted from the kinetic Monte Carlo model reported in 27 (where the energy scales attributed to alloy disorder and Bi atom clustering are given by ε 1 = 45 meV and ε 2 = 11 meV respectively). Although the contribution of the second Gaussian component appears very small at y = 0.003% it is essential to reproducing the plateau in the PL quenching, which is attributed to competing radiative and non-radiative processes in the offset Gaussian density of states 50 . The dashed lines in Fig.…”
Section: Presentation and Discussion Of Resultsmentioning
A comprehensive assessment of the nature of the distribution of sub band-gap energy states in bulk GaAsBi is presented using power and temperature dependent photoluminescence spectroscopy. The observation of a characteristic red-blue-red shift in the peak luminescence energy indicates the presence of short-range alloy disorder in the material. A decrease in the carrier localisation energy demonstrates the strong excitation power dependence of localised state behaviour and is attributed to the filling of energy states furthest from the valence band edge. Analysis of the photoluminescence lineshape at low temperature presents strong evidence for a Gaussian distribution of localised states that extends from the valence band edge. Furthermore, a rate model is employed to understand the non-uniform thermal quenching of the photoluminescence and indicates the presence of two Gaussian-like distributions making up the density of localised states. These components are attributed to the presence of microscopic fluctuations in Bi content, due to short-range alloy disorder across the GaAsBi layer, and the formation of Bi related point defects, resulting from low temperature growth.
“…Shakfa et al . suggest that this results from a two-component LDOS distribution, where at intermediate temperatures the radiative recombination of localised excitons from a deeper distribution of states balances the increasing non-radiative recombination as carriers in shallow states are excited above the mobility edge 50 . Evidence of a the dual-component distribution to the localised states is also observed by Imhof et al ., who show excellent agreement with experimental data using a kinetic Monte Carlo model taking into account exponential and Gaussian distributions on two energy scales to describe the hopping dynamics of carriers amongst the localised states 27 .Figure 4 (a) The thermal quenching of integrated luminescence intensity for varying incident excitation power.…”
Section: Presentation and Discussion Of Resultsmentioning
confidence: 99%
“…The energy scales of the two Gaussian distributions are in good agreement with those extracted from the kinetic Monte Carlo model reported in 27 (where the energy scales attributed to alloy disorder and Bi atom clustering are given by ε 1 = 45 meV and ε 2 = 11 meV respectively). Although the contribution of the second Gaussian component appears very small at y = 0.003% it is essential to reproducing the plateau in the PL quenching, which is attributed to competing radiative and non-radiative processes in the offset Gaussian density of states 50 . The dashed lines in Fig.…”
Section: Presentation and Discussion Of Resultsmentioning
A comprehensive assessment of the nature of the distribution of sub band-gap energy states in bulk GaAsBi is presented using power and temperature dependent photoluminescence spectroscopy. The observation of a characteristic red-blue-red shift in the peak luminescence energy indicates the presence of short-range alloy disorder in the material. A decrease in the carrier localisation energy demonstrates the strong excitation power dependence of localised state behaviour and is attributed to the filling of energy states furthest from the valence band edge. Analysis of the photoluminescence lineshape at low temperature presents strong evidence for a Gaussian distribution of localised states that extends from the valence band edge. Furthermore, a rate model is employed to understand the non-uniform thermal quenching of the photoluminescence and indicates the presence of two Gaussian-like distributions making up the density of localised states. These components are attributed to the presence of microscopic fluctuations in Bi content, due to short-range alloy disorder across the GaAsBi layer, and the formation of Bi related point defects, resulting from low temperature growth.
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