Atmospheric pressure-MOVPE growth of GaSb/GaAs quantum dots
| Autor: | Chinedu Christian Ahia, Ngcali Tile, Johannes R. Botha, Jaco Olivier |
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| Rok vydání: | 2018 |
| Předmět: |
010302 applied physics
Photoluminescence Materials science Atmospheric pressure business.industry 02 engineering and technology 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences Flattening Electronic Optical and Magnetic Materials Band bending Quantum dot 0103 physical sciences Optoelectronics Metalorganic vapour phase epitaxy Electrical and Electronic Engineering 0210 nano-technology business Excitation Wetting layer |
| Zdroj: | Physica B: Condensed Matter. 535:20-23 |
| ISSN: | 0921-4526 |
| Popis: | This study focuses on the growth of GaSb/GaAs quantum dots (QD) using an atmospheric pressure MOVPE system. For the best uncapped dots, the average dot height, base diameter and density are 5 nm, 45 nm and 4.5×1010 cm−2, respectively. Capping of GaSb QDs at high temperatures caused flattening and formation of thin inhomogeneous GaSb layer inside GaAs resulting in no obvious QD PL peak. Capping at low temperatures lead to the formation of dot-like features and a wetting layer (WL) with distinct PL peaks for QD and WL at 1097 nm and 983 nm respectively. Some of the dot-like features had voids. An increase in excitation power caused the QD and WL peaks to shift to higher energies. This is attributed to electrostatic band bending leading to triangular potential wells, typical of type-II alignment between GaAs and strained GaSb. Variable temperature PL measurements of the QD sample showed the decrease in the intensity of the WL peak to be faster than that of the QD peak as the temperature increased. |
| Databáze: | OpenAIRE |
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