Binding energy, electronic states, and optical absorption in a staircase-like spherical quantum dot with hydrogenic impurityH. Dakhlaoui, W. Belhadj, M. O. Musa and F. UnganEur. Phys. J. Plus, 138 6 (2023) 519DOI: https://doi.org/10.1140/epjp/s13360-023-04044-8