Performance degradation of InGaP solar cells due to 70 keV electron irradiation

Abstract

The performance of InGaP solar cells irradiated with electron beams at energies lower than the damage threshold is degraded. To investigate the irradiation effect, GaAs and InGaP solar cells are irradiated with 70 keV electron beams. Measurements of the electroluminescence and external quantum efficiency, in addition to the light current voltage measurement, are conducted. The results show that the performance of the InGaP solar cell, mainly open-circuit voltage, is degraded and affected by nonradiative recombination centers, while the performance of the GaAs solar cell is hardly degraded. The comparison of the experimental results with the prediction from the displacement damage dose model suggests that the non-ionizing energy loss of electrons is the main factor for evaluating the degradation of the InGaP cell caused by electron beams in a relatively low energy range.

Degradation prediction using displacement damage dose method for AlInGaP solar cells by changing displacement threshold energy under irradiation with low-energy electrons

“…In studies focusing on the DDD model, the effect of a change in the value of E d on the accuracy of degradation prediction has been frequently confirmed via irradiation tests, using high-energy electrons (1)(2)(3)(4)(5)(6)(7)(8)(9)(10). The E d of phosphorus is reported to be approximately 9 eV in the InGaP solar cells.…”

“…5) However, in our previous studies, it was observed that electrons at 60 keV generate radiation-induced defects resulting from the recoil of phosphorus atoms and thus cause the degradation of InGaP solar cells. [6][7][8] This unexpected degradation is probably caused by the incorrect value of displacement threshold energy (E d ) in NIEL.…”

Displacement damage dose analysis of the output characteristics of In0.5Ga0.5P and Cu(In,Ga)(S,Se)2 solar cells irradiated with alpha ray simulated helium ions

“…25) Previously, one of the authors used different displacementdamage threshold energies for Cu, In, Ga, and Se. 26,27) However, the differences in the calculated NIEL values are less than 20% for electrons and less than 2% for protons and He + ions. We confirmed that these differences do not significantly affect the analysis described in the next section.…”

Effects of He ion and electron beam irradiation on a CdTe solar cell dosimeter in a substrate configuration

“…Therefore, we have proposed a radiation measurement system based on dosimetry technology using a solar cell. [2][3][4] Solar cells have structures similar to those of semiconductor radiation detectors. Conventional semiconductor radiation detectors have relatively thick structures because the absorption coefficient of radiation is much smaller than that of sunlight in semiconductors.…”