Defect spectroscopy and non-ionizing energy loss analysis of proton and electron irradiated p-type GaAs solar cells

Abstract

Admittance spectroscopy combined with non-ionizing energy loss (NIEL) analysis is shown to be a powerful tool for analyzing solar cell radiation degradation, not relying on the change of macroscopic cell parameters. GaAs component cells, representative of the middle sub-cell in Ga 0.5 In 0.5 P/GaAs/Ge solar cells, were irradiated with protons and electrons in the 0.5-3 MeV energy range. Four irradiation-induced defects are identified in the p-type base layer. The nature of each defect is assessed by analyzing the dependence of its introduction rate on the NIEL deposited by electrons in the semiconductor. The expected linear relationship is only achieved if a unique threshold energy E d is ascribed to each defect, which ranges from 9 to 38 eV. An electron NIEL with E d = 21 eV, customarily used for GaAs-based solar cell degradation analysis, is an approximation of the relative abundance of these four defects. The 21 eV value is thus a GaAs material-specific parameter, independent of the electrical device design. In addition, the type and energy of the incident particle is correlated with the relative abundance of high E d defects. The impact of each defect on the macroscopic electrical parameters of the cell, namely the open-circuit voltage V OC , the short-circuit current density J SC and the recombination current density J 02 , is assessed with the help of a Pearson analysis. The different effectiveness of electron and proton irradiation on parameters dominated by recombination in the depleted region, such as V OC or J 02 , is attributed in part to the influence of the particle recoil spectra on the defect capture cross-section.

Proton radiation hardness of GaInAsP alloys for space solar cell applications

“…The different defect regeneration rate could be attributed to a different physical topology of the defects introduced by the two particles. The relativistic mass of the irradiating particle strongly influences the energetic content of the recoil spectrum generated by the particles, which in turn influences the defects generated in the material as already shown in GaAs 16 . In the 1 MeV electron case, low‐energy recoils up to few tens of eV are generated; thus, the damage is mainly constituted by isolated point‐defects closely spaced within the lattice.…”

“…In Figure 6B shown in GaAs. 16 In the 1 MeV electron case, low-energy recoils up to few tens of eV are generated; thus, the damage is mainly constituted by isolated point-defects closely spaced within the lattice. In the proton case, on the other hand, high-energy recoils in the range 0.1-1 keV are triggered, which cause long collision cascades and subsequent defect clustering effects.…”

Defect engineering using microwave processing in SiC and GaAs

“…The primary process, which determines defect production under irradiation, is a displacement of the atoms from the sites of the lattice. But the energy of a photon with frequency 2.45 GHz is about 10 −5 eV only; the threshold displacement energies in GaAs and SiC are (8-28) eV [74] and (20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35) eV [75], respectively. Therefore such a channel of microwave-induced modification of defect subsystem is unreal.…”

“…The performance of semiconductor devices is dictated ultimately by the presence and behavior of point defects. Defects in SiC and GaAs are under intensive study [20][21][22][23]. At the same time, more detailed information regarding the MWT influence on the deep level parameters is practically unknown.…”

POSS Polyimide Sealed Flexible Triple‐Junction GaAs Thin‐Film Solar Cells for Space Applications

“…[9,10] High-energy electrons and protons are the major concerns in HEO, which closely related to the interaction between radiation belt and solar activity. [11,12] For both LEO and HEO orbits, thermal cycling and ultraviolet (UV) irradiation also have impacts on spacecraft. [13,14] Besides, the gamma ray burst from far-away galaxy has high energy and strong penetration and reaches LEO and HEO.…”