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Origin of surface conductivity in diamond
1Institut fur Technische Physik, Universitat Erlangen, Erwin-Rommel-Strasse 1, D-91058 Erlangen, Germany.
Physical Review Letters
|October 13, 2000
Summary
Hydrogen-terminated diamond needs air exposure, not just hydrogen, for its high surface conductivity. A redox reaction in water acts as the electron sink, a unique semiconductor behavior.
Area of Science:
- Materials Science
- Surface Science
- Semiconductor Physics
Background:
- Hydrogen-terminated diamond displays high surface conductivity (SC).
- This conductivity is often attributed solely to hydrogen-related acceptors.
- The exact mechanism driving this phenomenon remains incompletely understood.
Purpose of the Study:
- To investigate the essential factors contributing to the high surface conductivity of hydrogen-terminated diamond.
- To propose and validate a novel mechanism for SC in hydrogenated diamond.
- To explain why hydrogenated diamond exhibits unique conductive properties compared to other semiconductors.
Main Methods:
- Experimental investigation of hydrogen-terminated diamond surfaces.
- Controlled exposure to air and analysis of surface conductivity.
- Development of a theoretical model based on redox reactions in adsorbed water layers.
Main Results:
- Experimental evidence shows that air exposure is crucial for SC, in addition to hydrogen termination.
- A proposed mechanism involves a redox reaction within an adsorbed water layer acting as an electron sink.
- This mechanism effectively explains the observed subsurface hole accumulation layer.
Conclusions:
- Surface conductivity in hydrogen-terminated diamond is a result of both hydrogen termination and air exposure.
- A redox reaction in adsorbed water is identified as the key electron sink mechanism.
- This finding highlights the unique conductive behavior of hydrogenated diamond among semiconductors.
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