Magnetic-field-induced photoluminescence enhancement in type-I quantum wells: A quantitative probe for interface flatness

Interfacial disorders in semiconductor quantum wells (QWs) determine material properties and device performance and have attracted great research efforts using different experimental methods. However, so far, there has been no way to quantify the lateral length distribution of the interfacial disorders in QWs. Since photoluminescence (PL) is sensitive to exciton localization, the evolutions of PL energy and linewidth under external perpendicular magnetic fields have served as effective measurement methods for QW analysis; however, the evolution of PL intensity has not played a matching role. In this paper, we develop a theoretical model correlating the PL intensity with the interfacial disorders of type-I QWs under an external perpendicular magnetic field. We verify the model’s rationality and functionality using InGa(N)As/GaAs single QWs. In addition, we derive the Urbach energy and determine the lateral length distribution of interfacial disorders. The results show that the magnetic field-dependent PL intensity, as described by our model, serves as a valid probe for quantifying the interface flatness. The model also reveals that the mechanism of magnetic-field-induced intensity enhancement is a joint effect of interfacial disorder-induced exciton localization and the transfer of excitons from dark to bright states. These insights may benefit performance improvements of type-I QW materials and devices.