A detailed investigation on the impact of variation in growth rate, monolayer coverage and barrier thickness on the optical characteristics of InAs/GaAs bilayer quantum dot heterostructures

作者：Basu N; Ghosh K; Kabi S; Sengupta S; Chakrabarti S^*

来源：Superlattices and Microstructures, 2013, 57: 150-157.

DOI：10.1016/j.spmi.2013.02.007

• Nanostructures
• Semiconductors
• Epitaxial growth
• Optical properties

We examined self-organized InAs/GaAs bilayer quantum dot (BQD) structures grown by solid source molecular beam epitaxy. The two layers had an intermediate GaAs barrier/spacer layer (SL) varying between 75 angstrom and 200 angstrom thicknesses. The photoluminescence (PL) characteristics of the InAs/GaAs BQDs were investigated by varying three growth parameters: (i) growth rate (monolayers per second, ML/s) of active dot layer, (ii) deposition amount (ML) of InAs on active dot layer while keeping that on the seed layer constant, and (iii) GaAs SL thickness (angstrom). Analysis of temperature-dependent PL data indicated an optimum SL thickness of similar to 100 angstrom, for which the low-temperature PL emission peak is at similar to 1.3 mu m with a full width at half-maximum of similar to 24.5 meV. BQD optimization was achieved with a slow (similar to 0.03 ML/s) rather than fast (similar to 0.3 ML/s) growth rate, and with a larger (3.2 ML) rather than smaller (2.5 ML) deposition of InAs on the active dot layer.

• 出版日期2013-5