Electrical performance of the InGaP solar cell irradiated with low energy electron beams

Abstract

The investigation of the radiation degradation characteristics of InGaP space solar cells is important. In order to understand the mechanism of the degradation by radiation the samples of the InGaP solar cell were irradiated in vacuum and at ambient temperature with electron beams from a Cockcroft‐Walton type accelerator at Osaka Prefecture University. The threshold energies for recoil were obtained by theoretical calculation. The energies and the fluences of the electron beams were from 60 to 400 keV and from 3×1014 to 3×1016 cm‐2, respectively. The light‐current‐voltage measurements were performed. The degradation of Isc caused by the defects related to the phosphorus atoms was observed and the degradation was suppressed by irradiation at an energy higher than the threshold energy for recoiling Indium atoms. At an energy of 60 keV, where the recoil does not occur, the Voc was degraded. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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.…”

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

“…The InGaP SJ solar cells were the same as those used in our previous studies. 16,17) The dimensions and physical properties of the InGaP and GaAs SJ solar cells are indicated in Table I. These samples did not have a cover glass or an anti-reflective coating on the surface.…”

“…These E th values well agree with those in the NIEL. 17,20) In this work, an electron energy of 70 keV, sufficiently lower than E th , is chosen to study the effects of irradiation on the InGaP and GaAs solar cells.…”

“…[12][13][14][15] To generate the radiation-induced defect of the InGaP cell, an electron energy higher than about 100 keV is required. 16) However, the performance of the InGaP cell, mainly open circuit voltage (V OC ), was found to be degraded by irradiation with 60 keV electron beams in a previous work, 17) where the degradation mechanism was not understood.…”