Well-defined excited states of self-assembled In As ∕ In Al Ga As quantum dots on InP (001)

• Published in: Applied physics letters 2005-07, Vol.87 (5), p.053102-053102-3
• Main Authors: Kim, Jin Soo, Lee, Jin Hong, Hong, Sung Ui, Kwack, Ho-Sang, Choi, Byung Seok, Oh, Dae Kon
• Format: Article
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.2005385

Self-assembled In As ∕ In Al Ga As quantum dots (QDs) in an InAlGaAs matrix on InP (001) substrates were grown by the alternate growth method (AGQD), where an InAs layer with a thickness of 1 monolayer (ML) and an InAlGaAs layer with a thickness of 1 ML were alternately deposited. Cross-sectional transmission electron microscopy images indicated that the aspect ratio (height/width) for the AGQDs was ∼ 0.25 , which was higher than ∼ 0.10 of conventionally grown InAs QDs. The photoluminescence (PL) peak position for the ground states of the AGQDs was 1.485 μ m with a linewidth broadening of 42 meV at room temperature, while the PL linewidth for the conventionally grown QDs was 85 meV . And the peaks for the excited-state transitions were also clearly observed from the excitation-power dependent PL. This is the first observation on the well-defined excited-state transitions from the InP-based InAs QDs, even though there were several reports on the features of the excited states.