Two-dimensional type-II BlueP/GaN heterostructure for solar cells: A first-principles study

The geometric structure, electronic and optical properties, power conversion efficiency (PCE) of the BlueP/GaN heterostructure and its response to biaxial strain and electric field are systematically studied based on first-principles calculations. The results show that all configurations are found to be semiconductors with indirect band gaps of 1.34, 1.79, 1.20 and 1.40 eV, respectively. The BlueP/GaN heterostructure possesses excellent carrier mobility. The electron mobility of AA' configuration is up to 3.329 m2⋅V−1⋅s−1, while the hole mobility can reach 1.707 m2⋅V−1⋅s−1. The visible light absorption intensity of the BlueP/GaN heterostructure can significantly improve compared with the corresponding monolayers. The maximum adsorption coefficient of AA configuration can attain to 1.01 × 105 cm−1 at the 422 nm visible light. Especially, the tunable band gap and type-II band alignment are achieved through biaxial strains and external electric fields. The BlueP/GaN heterostructure can achieve 24.13% PCE at 4% tension strain. External electric fields can more accurately modulate the band gap to dynamically control electronic properties of BlueP/GaN heterostructure. Hence, the results not only provide theoretical basis for sustainable energy application of BlueP/GaN heterostructure, but also provide motivation to experimentally explore BlueP/GaN heterostructure for harvesting green, abundant and clean solar energy.