| Samples | n | Eg1 (eV) | Eg2 (eV) |
| DKRN-Si | 3.47 | - | 1.05 |
| DKRN-NW | 2.37 | - | 2.50 |
| DKRN-Gel | 2.40 | 1.90 | 2.80 |
| DKRN-UD | 2.44 | 2.10 | 3.10 |
| DKRN-D | 2.60 | 2.10 | 3.20 |