Here, we report that the tensile strain in silicon nanocrystals embedded in silicon nitride significantly changes the size-dependent evolution of the conduction and valence energy levels, compared with strain-free silicon nanocrystals. Using capacitance spectroscopy, the quantum-confined energy shifts in the conduction and valence levels were identified as Delta E-C(eV) = 11.7/d(2), and Delta E-V(eV) = -4.5/d(2), where d is the mean diameter of the silicon nanocrystals in nanometers. These findings indicated that the tensile strain in the silicon nanocrystals significantly increased the quantum confinement, by a factor of 3.3 in the conduction levels, and by a factor of 1.8 in the valence levels. (C) 2017 Elsevier B.V. All rights reserved.