Ultrahigh vacuum scanning tunnelling microscopy studies of the decapped InAs quantum dots on GaAs(001) surface after desorption of a protective As layer
✍ Scribed by Bolotov, L. N.; Nakamura, A.; Evtikhiev, V. P.; Tokranov, V. E.; Titkov, A. N.
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 372 KB
- Volume
- 27
- Category
- Article
- ISSN
- 0142-2421
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✦ Synopsis
The morphology and electronic properties of InAs quantum dots (QDs) on the GaAs(001) surface has been studied by ultrahigh vacuum scanning tunnelling microscopy/spectroscopy after removal of a preliminary deposited protective As layer. A thermal annealing procedure has been developed, which, applied to a sample with an As cap layer, allows InAs QDs to be opened on the surface of an InAs wetting layer (WL) exhibiting a [ 2 Â 4 ] reconstruction of As dimers. Scanning tunnelling spectroscopy measurements on the decapped surface show that I-V characteristics taken with the microscope tip positioned over single InAs QDs have a smaller voltage width for zero conductivity (dI/dV = 0) when compared with those taken over the InAs WL, which are essential the same as the I-V characteristics for a clean GaAs surface. This observation seems to indicate a weakening of the surface band bending in the areas beneath InAs QDs.