Tunnel junction limited performance of InGaAsN/GaAs tandem solar cell

Comparison between various structures of dilute-nitride InGaAsN quantum well lasers in terms of their main electronic properties

“…Recently, experiments concentrated primarily on the performance of solar cells based on InGaAsN, with a few applications towards the improvement of the InGaAsN alloy properties and others analyzing the performance of p-i-n photodiodes based on the same quaternary lattice. Thus, based on the InGaAsN material system, different groups of researchers fabricated and characterized multijunction InGaAsN solar cells using the process of MBE (molecular beam epitaxy) and obtained an improved threshold current density as compared to previous attempts [1]; analyzed the causes for the degradation of performance due to the tunnel junctions in InGaAsN/GaAs tandem solar cells [2]; characterized the effects of irradiation on InGaAsN solar cells, by studying the dilute nitride layers prior to and after a 1-MeV electron irradiation and found out that 94% of the initial photocurrent is retained, together with no negative effects on the other optoelectronic properties of the device [3]; also characterized the effects of 1-MeV proton irradiation and remarked a 28% decrease of the photocurrent, due to defects created both in the InGaAsN absorber and GaAs emitter layers, and an increase of the hardness of the proton radiation of InGaAsN with the increase of the nitrogen content [4]; modified the properties of dilute-nitride InGaAsN alloys by neutralizing the effect of nitrogen by the addition of hydrogen atoms and remarked that this process is hindered proportional to the increase of the number of bonds between indium and nitrogen, thus proposing a new approach to explain the defects in these structures [5]; studied the performance improvement of the frequency response of p-i-n photodiodes based on a lattice of InGaAsN matched to GaAs, with a 2% content of nitrogen and 6% of indium [6].…”

As-Grown InGaAsN Subcells for Multijunction Solar Cells by Molecular Beam Epitaxy

“…However, the InGaAsN solar cells reported in those studies require annealing after the MBE growth, which can be a problematic step to implement during MJSC monolithic growth. Indeed, degradation of tunnel junctions [21], [22], [23], dopant out-diffusion [24] and InGaAsN bandgap blueshift [25] are multiple issues that can occur after thermal annealing.…”

A Theoretical Model for Voltage-Dependent Photocurrent Collection in CdTe Solar Cells

“…In thin-film solar cells, photocurrent collection losses can be extremely significant due to their high absorption coefficient, short absorption lengths, small depletion widths, and short diffusion lengths [1]. Voltage-dependent photocurrent collection losses have been observed in all thin-film solar cells, including those based on Cu 2 S, CuInSe 2, CdTe, organic P3HT/PCBM, and inorganic III-V solar cells [2][3][4][5][6]. The physical model of classic silicon solar cells assumes that the photo-generated current is a constant, independent of the cell's output voltage.…”