Quantum dots are zero dimension material, if the thickness of material is reduced less than 10 micron along x and y axis then we will get one dimensional wire
In Bulk material(Silicon, CdTe) that are being used as absorbing material, the bandgap is fixed. If you replace it with Quantum Dots, you get tunable bandgap across a wide range of energy level with change in their size.
Since you're changing its size, it's no longer confined to 0D.