کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5354261 | 1503684 | 2013 | 5 صفحه PDF | دانلود رایگان |
- THz surface emission spectroscopy is used as a new surface research tool for the study of semiconductor surfaces.
- The surfaces under study are fresh, native oxidized, and octadecanthiol (ODT) passivated ones from (1Â 0Â 0) surface of GaAs.
- Self-assembled ODT monolayer can stabilize GaAs (1Â 0Â 0) surface, and maintain a THz surface emission 1.4 times as efficient as the native oxidized surface.
- Passivation of the surface can reduce the built-in electric field in the GaAs (1Â 0Â 0) surface.
Terahertz (THz) emission from octadecanthiol (ODT) passivated (1Â 0Â 0) surface of the semi-insulating GaAs was measured, and compared with those from the native oxidized and the fresh surfaces. It was shown that the self-assembled ODT monolayer can stabilize the GaAs (1Â 0Â 0) surface, and maintain a THz surface emission 1.4 times as efficient as the native oxidized surface under equal conditions. Surface passivation can reduce the built-in electric field in the depletion region of the GaAs (1Â 0Â 0), resulting in the suppression of the THz radiation to a different extent. Oxidation of GaAs surface reduces the THz amplitude mainly in the low-frequency region. These results indicate that GaAs can be made a more effective THz source by choosing molecular passivation technique. Conversely, the THz emission features such as polarity, amplitude, and phase from molecule-passivated surfaces may be used to characterize the attached molecules.
Journal: Applied Surface Science - Volume 279, 15 August 2013, Pages 92-96