High Efficiency Dilute Nitride Solar Cells: Simulations Meet Experiments

Abstract

Parameter extraction procedure and simulation of dilute nitride solar cells are reported. Using PC1D simulation and fitting to experimental current-voltage and external quantum efficiency data, we retrieve the phenomenological material parameters for GaInNAs solar cells. Based on these, we have constructed a model that can explain the changes in short circuit current and open circuit voltage of n-i-p solar cells subjected to rapid thermal annealing. The model reveals that non-annealed MBE-grown GaInNAs material has an n-type doping that evolves to p-type upon rapid thermal annealing. The change of doping type and the shift of the physical location of the pn-junction were confirmed by Kelvin-probe force microscopy. The PC1D modelling was found to work well also for GaInNAs p-in solar cells with opposite polarity. It was also found that the GaInNAs lower doping levels in p-in solar cells grown at lowered As/III flux ratios were associated with increased carrier lifetimes.

Lattice‐matched four‐junction tandem solar cell including two dilute nitride bottom junctions

“…The estimation is based on the fitting of the PC1D modeled EQE data to the actual EQE performance of the bottom cell. Details for PC1D modeling of single junction dilute nitride cells are reported elsewhere . Extremely good correlation between the measured and PC1D‐simulated EQE curves was obtained with 5 × 10 14 cm −3 background doping level and with 2 to 4‐nanosecond lifetimes (see Figure A).…”

Chemical approaches for electronic doping in photovoltaic materials beyond crystalline silicon

“…Through the MBE-grown strategy, a higher electron diffusion length of 0.5 mm was achieved in GaInNAs. 338 This strategy has also been applied in newgeneration solar cells. 150,205 In addition, extrinsic dopants may command nucleation and crystallization during film growth, thus controlling the bulk defect, especially for films fabricated by the solution process.…”