Excited-state optical absorption in modified Kratzer–ring-shaped quantum dots

We investigate the optical absorption coefficient of spherical semiconductor quantum dots confined by a modified Kratzer-ring-shaped potential (MKRSP). The ring-shaped term introduces angular anisotropy that reshapes the low-lying spectrum and modifies dipole-allowed transitions beyond conventional radial confinement models. Analytical solutions of the Schrödinger equation are obtained via the Nikiforov–Uvarov method, enabling closed-form evaluation of intra- and inter-band absorption. The confinement parameters r 0 and V 0 independently tune effective dot size and confinement depth, while the ring-shaped contribution activates additional transitions and enhances spectral weight. Increasing temperature reduces the occupation difference between states, suppressing intra-band peaks and broadening the spectra, whereas inter-band transitions remain comparatively robust. These results demonstrate that MKRSP confinement provides multi-parameter control of spectral position and oscillator strength beyond purely central potentials.