Abstract
Effects of a humid environment on the degradation of semiconductors were studied to understand the role of the surface charge on material stability. Two distinctly different semiconductors with the Fermi level stabilization energy EFS located inside the conduction band (CdO) and valence band (SnTe) were selected, and effects of an exposure to 85 °C and 85% relative humidity conditions on their electrical properties were investigated. Undoped CdO films with bulk Fermi level EF below EFS and positively charged surface are very unstable. The stability greatly improves with doping when EF shifts above EFS, and the surface becomes negatively charged. This charge-controlled reactivity is further confirmed by the superior stability of undoped p-type SnTe with EF above EFS. These distinct reactivities are explained by the surface attracting either the reactive OH- or passivating H+ ions. The present results have important implications for understanding the interaction of semiconductor surfaces with water or, in general, ionic solutions.
Original language | British English |
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Pages (from-to) | 32543-32551 |
Number of pages | 9 |
Journal | ACS Applied Materials and Interfaces |
Volume | 11 |
Issue number | 35 |
DOIs | |
State | Published - 4 Sep 2019 |
Keywords
- CdO
- Fermi stabilization energy
- moisture degradation
- semiconductor stability
- SnTe
- surface charge determined stability
- surface charge layer