Two-layer photo-thermal deflection model to study the non-radiative recombination process: Application to Ga0.7In0.3As0.23Sb0.77/GaSb and Al0.3Ga0.7As0.08Sb0.92/GaSb laser structures

International audiencePhoto-thermal deflection technique is used to study the nonradiative recombination process in laser structures Ga0.7In0.3As0.23Sb0.77 and Al0.7Ga0.3As0.08Sb0.92 grown by molecular beam epitaxy on GaSb substrate. A two layer theoretical model has been developed, taking into account both thermal and electronic contributions in the photothermal signal; the coincidence between experimental curves giving the normalized amplitude and phase variations versus square root modulation frequency to the corresponding theoretical ones permits to determine non-radiative lifetime, electronic diffusivity, and surface and interface recombination velocities

Improvement of carriers diffusion length and mobility in annealed GaAsPN materials for intermediate band solar cells.

International audienceIn this paper, we investigate the effect of thermal annealing on nonradiative recombination parameters ofGaAsPN materials used for intermediate band solar cells. This study is performed thanks to photothermaldeflection technique PTD. Indeed, nonradiative lifetime, electronics diffusivity, surface and interface recombination,are extracted through a good fit between theoretical and experimental amplitude and phase of PTDsignal. Then, the effects of annealing temperature on charge transport were analyzed and discussed. As animportant result for solar cells improvement, we have found that hole diffusion length and mobility increasesrespectively from 13.8 to 19 (+/-2.5%) μm and from 112 (+/-4.9%) to 153 (+/-3.5%) cm2/V⋅s for GaAsPN as grown tothat annealed at 800 °C

Non-radiative recombination process in BGaAs/GaAs alloys: Two layer photothermal deflection model

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Photothermal deflection spectroscopy (PDS) investigation of optical and thermal properties of BGaAs/GaAs alloys

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Shift of the gap energy and thermal conductivity in BGaAs/GaAs alloys

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Shift of the gap energy and thermal conductivity in BGaAs/GaAs alloys

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RTA effects on optical absorption and thermal conductivity of GaAsPN grown on GaP for tandem solar cell applications

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GaAsPN Absorbers Grown on GaP for Multijunction Solar Cells: Optical Absorption and Thermal Conductivity Properties

International audienceOptical absorption and thermal conductivity of GaAsPN absorbers grown on GaP are investigated by optical absorption spectroscopy and photo‐thermal deflection spectroscopy (PDS). First, the strong dependence of optical absorption on As content is shown: with a maximum absorption coefficient of 38,000 cm‐1 below the GaP bandgap. Optical absorption and thermal conductivity of the samples are then evaluated for various growth and annealing conditions using PDS. The significantly positive impact of annealing on both properties is demonstrated. Thermal conductivity reached 4W/mK for the best sample. These results are promising for the development of absorbers in multijunction solar cells