Abstract
Factors determining etching and passivation of n-type InP in H2SO4 and HCl solution and the corresponding surface chemistry are considered. Passivation is favoured by higher light intensity and lower proton and Cl− ion concentration. Ex-situ surface analysis shows the passive (bi)layer to consist mainly of oxide-based In3+ and P5+ components: InPO4 and In(PO3)3. Hydrodynamics is found to play a decisive and surprizing role in determining the kinetics of the surface reactions. Oxygen-bridge formation between surface In and P atoms, as a result of deprotonation of a P-OH reaction intermediate, is considered to be important in determining competition between the two reaction paths: etching and passivation. These results are compared with markedly contrasting results for n-type GaAs under similar experimental conditions.
Original language | English |
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Article number | 136872 |
Number of pages | 13 |
Journal | Electrochimica Acta |
Volume | 360 |
DOIs | |
Publication status | Published - 10 Nov 2020 |
Keywords
- Anodic oxidation
- GaAs
- InP
- Native oxide
- Passivation
- Surface chemistry