Strain-Induced Quenching of Optical Transitions in Capped Self-Assembled Quantum Dot Structures
نویسندگان
چکیده
Strain-induced quenching of optical transitions has been found in capped self-assembled quantum dot structures. Light absorption at the E1 and E1 1 D1 critical points of InSb islands buried in InP disappears for nominal InSb thicknesses lower than 10 monolayers as a consequence of the strain produced inside the islands by the cap layer. Certainly, this strain increases as the InSb deposition diminishes, changing the band lineup of the system from type-I to type-II and therefore drastically reducing the oscillator strengths of the island-related E1 and E1 1 D1 transitions. [S0031-9007(97)05086-2]
منابع مشابه
Growth, structural, and optical properties of self-assembled (In,Ga)as quantum posts on GaAs.
Self-assembled quantum dots embedded in semiconductor heterostructures have proved to be a rich system for exploring the physics of three dimensionally confined charges and excitons. We present here a novel structure, which allows adjusting the level of confinement between 3D and 2D for electrons and holes, respectively. The quantum post consists of a quantum dot connected to a short quantum wi...
متن کاملExperimental and Theoretical Study of Polarization-Dependent Optical Transitions in InAs Quantum Dots at Telecommunication-Wavelengths (1300-1500 nm)
The design of some optical devices, such as semiconductor optical amplifiers for telecommunication applications, requires polarization-insensitive optical emission at long wavelengths (1300–1550 nm). Self-assembled InAs/GaAs quantum dots (QDs) typically exhibit ground state optical emissions at wavelengths shorter than 1300 nm with highly polarization-sensitive characteristics, although this ca...
متن کاملOptical phonons in self-assembled Ge quantum dot superlattices: Strain relaxation effects
We present Raman scattering by optical phonons in self-assembled Ge quantum dot superlattices grown by solid-source molecular beam epitaxy. The Ge quantum dots are vertically correlated and have different average sizes and dot morphologies. The GeGe optical phonon frequency was mainly caused by strain relaxation effects. Experimentally observed GeGe optical phonon modes were compared with calcu...
متن کاملBias-Induced Optical Absorption of Current Carrying Two-Orbital Quantum Dot with Strong Electron-Phonon Interaction (Polaron Regime)
The one photon absorption (OPA) cross section of a current carrying two-orbital quantum dot (QD) with strong electron-phonon interaction (polaron regime) is considered. Using the self-consistent non-equilibrium Hartree-Fock (HF) approximation, we determine the dependence of OPA cross section on the applied bias voltage, the strength of effective electron-electron interaction, and level spacing ...
متن کاملPhonon pressure coefficient as a probe of the strain status of self-assembled quantum dots
The built-in strain in self-assembled quantum dots has large impact on their physical properties, but both its average value and degree of anisotropy are often unknown. The authors demonstrate that the pressure coefficient of optical phonons might be used as probe for the strain status of the dots. This method was applied to the case of Ge dots capped with Si layers of different thicknesses. Th...
متن کامل