Effect of Photon Recycling on Diffusion Length and Internal Quantum Efficiency in AlxGa1-xAs–GaAs Heterostructures

The photon recycling process, i.e., the excitation of electron-hole pairs by the reabsorption of luminescent light, has large effects on the determination of the minority carrier diffusion length L and the internal quantum efficiency ηin GaAs with a high quantum efficiency. In this report, we show that the separate treatments of L and ηin cause the erroneous results for materials with high quantum efficiency. We developed a consistent method of evaluating the photon recycling effects on both ηin and L, based on the simultaneous measurements of the external quantum efficiency ηex and the photo-excited current under the short circuit condition Isc. This method was applied to the specimens with single heterestructure (p-AlxGa1-xAs-p-GaAs-n-GaAs) prepared by the liquid phase epitaxial (LPE) process.