Modeling of the tandem III–V dilute nitride bulk or quantum engineered/silicon solar cells

Abstract

Tandem silicon solar cells are designed in order to lower the levelized cost of solar electricity by increasing the cell’s efficiency to more than 30%. Dual junction thin film III–V/Si cell efficiencies are limited to 20% because of high dislocation densities (>106 cm−2) due to lattice mismatch between them. GaAsyP1−x−yNx has a lattice constant matched with silicon at y = 4.7*x − 0.1 and has an optimal bandgap i.e. between 1.7 and 1.9 eV for tandem III–V’s with Si. This work designs a p-i-n GaAsPN/GaP symmetric or asymmetric (resonant thermos tunneling) multi-quantum well (MQW) device for a top sub-cell of a dual junction silicon tandem to minimize the effect of the degraded minority carrier transport properties of bulk dilute nitride layers and presents the simulated solar cell properties using a realistic drift-diffusion approach. Using extracted experimental spectral responses as well as other solar cell parameters of various silicon solar cell like: HIT, PERC, IBC etc, the tandem efficiencies of designed p-i-n MQWs devices in conjunction with silicon solar cells have been evaluated. The tandem efficiency of an optimized p-i-n MQWs device under AM 1.5 G spectrum can exceed 33% when in conjunction with a 25.6% efficient HIT silicon solar cell.