Local optical spectroscopy of self-assembled quantum dots using a near-field optical fiber probe to induce a localized strain field

Abstract

Articles you may be interested inCharacterization of self-assembled InAs quantum dots with InAlAs ∕ InGaAs strain-reduced layers by photoluminescence spectroscopy J. Appl. Phys. 97, 083511 (2005); 10.1063/1.1886278Photoluminescence studies of type-II self-assembled In 0.55 Al 0.45 As/Al 0.5 Ga 0.5 As quantum dots grown on (311)A GaAs substrateWe introduce and demonstrate a novel operating mode in near-field optical microscopy. The tip is used to simultaneously optically probe the sample and induce a highly localized strain in the area under study by pushing the tip into the sample. From knowledge of total tip-sample compression and tip geometry, we estimate the magnitude of stress, and show that localized uniaxial-like stresses in excess of 10 kbar can be achieved. We apply this method to a sample of InAlAs self-assembled quantum dots. A blueshift of quantum dot emission lines consistent with estimates of the strain is observed, as well as a quenching of the photoluminescence with strain.

Lateral Coupling of Self-Assembled Quantum Dots Studied by Near-Field Spectroscopy

“…Due to the lattice mismatch between the two materials, the strain is relieved during growth by the formation of islands in the quantum well, resulting in a disordered array of quantum dots laterally connected by the quantum well, which is also known as the wetting layer (WL). This particular sample used here has previously been studied extensively [9][10][11][12][13], and the dot density is known to be 2·10 10 cm -2 , the average dot radius is approximately 9 nm, and the ground state and the first excited state are separated by about 40 meV.…”

Tuning of emission energy of single quantum dots using phase-change mask for resonant control of their interactions

“…Using a scanning probe tip as an indenter is one possible approach [20,21], though it is inconvenient in practice because it requires a feedback control mechanism, which makes the integration difficult. An alternative method of applying a local strain field to selected individual QDs is needed.…”

Nanoindentation effect on the optical properties of self-assembled quantum dots

“…Near-ÿeld scanning optical microscopy (NSOM), for example, is used to excite or collect near-infrared emitted light from small groups of nanometer scale quantum dots and is able to resolve the emission characteristics of individual dots (Robinson et al, 1998;Robinson et al, 2001). The microscope tip used in NSOM is a tapered optical ÿber with a at aperture having a diameter much smaller than a micron.…”