Ⅲ-Ⅴ dilute nitride quantum-engineered solar cell for lattice-matched siliconbased tandems

摘要

This work investigates 1.7eV- 1.9 eV devices lattice matched to silicon where a p-i-nGaP solar cell, fabricated with an i-region that comprises a plurality of resonantly coupledquantum well of GaAsPN/GaP and investigates the evolution of the performance of thesedevices operating in tandem configuration with variety of advanced high efficiency silicon solarcells (i.e. HIT, PERC, PERT etc.).The band structures, evolution of bandgaps, and confinementenergies are calculated using eight band k.p Hamiltonian that combines a Band Anti-Crossingmodel accounting for the incorporation of dilute amounts of nitrogen in the host matrix of aKane-like semiconductor. The confinement energies are derived using a transfer matrixformalism and an envelope function approximation. Considering all possible electron/holetransitions, the optical absorption for coupled quantum well material systems are evaluated usingthe Fermi golden rule. Next, the performances of the targeted devices are analyzed within theframework of drift-diffusion model that incorporates realistic parameters extracted from pastexperiment along with demonstrated spectral response and I-V characteristic of record Si bottomcells. The study then explores the parameter design space and illumination conditions (AM0,AM1.5 and concentration) and identifies optimal parameters for achieving highest possibleefficiency for each type of Si bottom cell. The study indicates the potential for 1 sun efficienciesexceeding 33% and 35% for series-connected two terminals and 4 terminal tandems respectively.