摘要Extremely low density InAs quantum dots (QDs) are grown by molecular beam droplet epitaxy. The gallium deposition amount is optimized to saturate exactly the excess arsenic atoms present on the GaAs substrate surface during growth, and low density InAs/GaAs QDs (4×106cm -2) are formed by depositing 0.65 monolayers (MLs) of indium. This is much less than the critical deposition thickness (1.7ML), which is necessary to form InAs/GaAs QDs with the conventional Stranski--Krastanov growth mode. The narrow photoluminescence linewidth of about 24meV is insensitive to cryostat temperatures from 10K to 250K. All measurements indicate that there is no wetting layer connecting the QDs.
Abstract：Extremely low density InAs quantum dots (QDs) are grown by molecular beam droplet epitaxy. The gallium deposition amount is optimized to saturate exactly the excess arsenic atoms present on the GaAs substrate surface during growth, and low density InAs/GaAs QDs (4×106cm -2) are formed by depositing 0.65 monolayers (MLs) of indium. This is much less than the critical deposition thickness (1.7ML), which is necessary to form InAs/GaAs QDs with the conventional Stranski--Krastanov growth mode. The narrow photoluminescence linewidth of about 24meV is insensitive to cryostat temperatures from 10K to 250K. All measurements indicate that there is no wetting layer connecting the QDs.
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2007, Vol. 24 
