Annealing and Hydrogenation of GaNP Lattice Matched to Si

GaN 0.02 P 0.98 is a promising top junction material for a Si-based tandem solar cell, offering the correct lattice constant and bandgap for an optimal three-terminal device. A key challenge for dilute nitride materials is achieving sufficiently high carrier lifetimes. This paper presents a detailed investigation of the carrier lifetimes in GaNP lattice matched to Si as well as a novel hydrogenation treatment. The lifetimes are over 20 ns at 10K, but the TRPL signal becomes undetectable at 140K due to increased nonradiative recombination. While annealing boosts the carrier lifetime, subsequent hydrogenation was seen to neither increase nor decrease lifetime.