Speaker
Description
High-index substrates have long been of interest due to their surface physical properties. For example, GaAs (n11) surfaces with n = 1, 2, 3, … have provided promising results in solar cells demonstrating higher efficiency, terahertz devices, and have been employed in heteroepitaxial growth on GaN.
In this work, we focused on the investigation of growing AlGaAs/GaAs heterostructures on GaAs (811) substrates. The (811) surface can be seen as composed of narrow terraces of the crystal plane (100) with a width of 1.6 nm. Reflection high-energy electron diffraction (RHEED) patterns exhibit split streaks with the characteristic symmetry of the (100) surface, misoriented by an angle of 10° with respect to the [100] direction.
Heterostructures growth was performed using an MBE Riber C21 system. By varying the temperature range and V/III flux ratio, we explored changes in the characteristics of the epitaxial layers.
Atomic force microscopy (AFM) showed that during the growth of GaAs on (811) substrates, surface morphology can vary significantly depending on specific growth parameters, yielding either flat surfaces or surfaces that exhibit macroscopic faceting. After the homoepitaxy process, AlGaAs/GaAs quantum well (QW) structures were grown at a very high substrate temperature (Tg = 680°C).
AFM images showed the formation of facets up to 10 µm in length. The photoreflectance spectrum of the QW structure was dominated by optical interference. By performing FFT filtering, a better spectrum was obtained, allowing us to clearly observe electronic transitions in the QWs. Further results on the characterization of these structures will be shown and discussed.
Reference
Control of the formation of self-assembled nano-voids at the GaN/GaAs interface.
Briseida G. Pérez-Hernández, Mario A. Zambrano-Serrano, Salvador Gallardo-
Hernández, Yenny L. Casallas-Moreno, Ángel Guillén-Cervantes and Máximo López-
López, Applied Physics Express 2021 14 (8), 085507.
This work was supported by
Conahcyt
| Keywords | GaAs, AlGaAs, RHEED, QW |
|---|---|
| Author approval | I confirm |
| Author will attend | I confirm |
