Intersubband transition energy is computed for both core-shell quantum dot (CSQD) and binary capped core-shell quantum dot (CCSQD) of cubic geometry by solving the time-independent Schrodinger equation using the finite difference method. The discretization of the structures in all three spatial directions generates sparse Hamiltonian matrices, which are diagonalized to obtain energy eigenstates for the conduction band. The transition energy for the lowest three energy eigenstates is compared for different structural parameters considering GaAs / Al0.42Ga0.58As CSQDs. CSQD capped with AlAs (CCSQD) viz GaAs / Al0.42Ga0.58As / AlAs shows higher eigenstates and transition energy, which decreases with the increase in core thickness. Furthermore, the optical properties of these structures have been investigated which are in concurrence with the obtained eigen energy. The broader tuning range and blueshifted higher absorption coefficient of CCSQD support significant application in quantum dot detectors and lasers.