Effect of band anisotropy on electronic structure of PbS, PbSe, and PbTe quantum dots

Abstract

We have calculated the electronic structure of spherical PbS, PbSe, and PbTe quantum dots using a fourband envelope-function formalism that accounts for band anisotropy. By comparing our results with an analytical calculation that assumes a spherical approximation of the k ជ •p ជ Hamiltonian, we show that the effects of band anisotropy are more pronounced for the excited states and increase with the confinement. We also show how the same technique can be applied to ellipsoidal quantum dots.

Quantum noise in the electromechanical shuttle: Quantum master equation treatment

“…Unfortunately, the lowest exciton level is often an optically forbidden transition, or dark state, 46 which causes additional dephasing and even exciton trapping in many different quantum dots. This obstacle does not seem to be present for the IV-VI lead chalcogenide nanocrystals, [47][48][49][50] which is very promising.…”

Solid‐state 207Pb NMR studies of lead‐group 16 and mixed transition‐metal/lead‐group 16 element‐containing materials

“…Lead selenide, for example, is used as a photodetector 1 and for other mid-infrared optoelectronic devices. 2 Quantum dots of PbSe 3,4 have been formed by controlling synthetic parameters such as reaction temperature and layer thicknesses. Lead chromate, formed as both nanorods and microparticles, 5 is an important material used as a photosensitizer.…”

Measurement of electronic splitting in PbS quantum dots by two-dimensional nonlinear spectroscopy

“…In lead-salt QDs, the direct-band gap lies at four equivalent L points in the Brillouin zone, creating a 64-dimensional excitonic manifold when spin is included 5 . At the band edge, minor deviations from spherical symmetry as well as band anisotropy 6,7 may give rise to splitting of degenerate energy levels, especially for small QDs. Intervalley coupling and interband coupling 8 as well as electron-hole Coulomb and exchange interactions 9 can further split the excitonic energy levels.…”

“…The principle behind the GRAPES technique is shown schematically in Figure 2 and discussed in detail elsewhere. [15][16][17] The basic idea 6 involves encoding the first temporal delay (corresponding to equally-spaced coherence times) of the 2D pulse sequence along a spatial axis of a macroscopically homogeneous sample. The photon echo signal is emitted in a line across the sample, rather than from a single point.…”