Hydrogen trapping and passivation of intrinsic acceptor defects in the chalcopyrite
Phys. Rev. Materials 10, 054603 – Published 19 May, 2026
DOI: https://doi.org/10.1103/gn4l-4c45
Abstract
Hydrogen is an element frequently found within the lattice of the (CIS) chalcopyrite and its alloys in solar-cell devices, in many occasions introduced intentionally to passivate the electrical activity of existing defect centers. The present study reports first-principles calculations of the formation energies of the intrinsic defects of the CIS compound and their interaction with hydrogen. This interaction was also studied by analyzing muon-spin spectroscopy observations that probed the evolution of the spin relaxation of this lighter hydrogenic isotope. The calculations covered an extended range of growth conditions and regions of the CIS phase diagram, through the elemental chemical potentials, leading to -type and -type material. From the final results, the most plausible trapping centers for monatomic hydrogen were identified through a self-consistent solution of the electroneutrality equation as a function of the growth conditions. The copper vacancies were found to be the defects with the higher concentration for -type and -type CIS, with the exception of copper-rich and maximally indium-poor conditions, where the Cu-to-In antisite strongly competes as the dominant acceptorlike defect. Defect association of hydrogen with both of these acceptor defects led to trapping with full and partial passivation, respectively, and binding energies of eV for the resulting defect complexes. The calculated energy landscape of the hydrogen interaction with the copper vacancy contains two energy minima, which control the local diffusion pathways and trapping energy of hydrogen at this defect. Calculations based on the nudged elastic-band method and transition-state theory led to the local trapping and detrapping energy barriers and associated dissociation temperature. The analysis of the muon-spin data showed clear evidence of muon trapping at native defects in the CIS lattice with the copper vacancy providing the best match of the calculated muon-spin relaxation with the experimental value.
