| Passivation method | Thickness of sulfur passivation layer (MLs) | ||
| Untreated | — | 0 | |
| Na2S + H2O | 20˚C | 0.4 | |
| Na2S + H2O | 100˚C | 0.7 | |
| Na2S + C2H4(OH)2 | 20˚C | 1.1 | |
| Na2S + C2H5OH | 20˚C | 0.8 | |
| Na2S + C3H7OH | 20˚C | 1.3 | |