Reversible GaInP2 Surface Passivation by Water Adsorption: A Model System for Ambient-Dependent Photoluminescence

The photoluminescence (PL) intensity of semiconductors can be modulated by their ambient. We show GaInP₂ to respond reversibly to water vapor, irreversibly to oxygen, and with a time dependence to air. We characterize the reversible PL response to water vapor in a set of steady-state measurements that reveal a systematic dependence on pressure. We derive a model for this behavior based on Langmuir adsorption and Shockley-Read-Hall recombination principles to describe how partial pressure controls luminescence. The expression for the GaInP₂/water vapor system shows excellent agreement to measurements. Combined, the PL monitoring technique and model demonstrate a quantitative approach for probing gas/surface defect interactions of semiconductor processing steps, luminescence-based sensors, and photocatalytic surfaces.