The energy level spacing between the ground and first excited states in InAs/GaAs quantum dots as a measure of the zero dimensionality

We suggest a figure of merit for the zero dimensionality, which is the most important property in quantum dots (QD). QD samples emitting at longer wavelengths are turned out to have the larger energy level spacings between the ground and first excited states. The QDs have the stronger quantum effect likely due to the taller height and are closer to an ideal zero-dimensional system.