Electronic states and optical gain in strained CdS/ZnS quantum structures

Woggon, U.; Petri, W.; Dinger, A.; Petillon, S.; Hetterich, M.; Grün, M.; O’Donnell, K. P.; Kalt, H.; Klingshirn, C.

doi:10.1103/physrevb.55.1364

Cited by 50 publications

(16 citation statements)

References 8 publications

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“…However, this passivation can still be incomplete, retaining abrupt lattice imperfections that enable nonradiative relaxation pathways. Alternatively, other reports have described the formation of an internal semiconductor core that is coated with a shell of a different semiconductor (named core-shell structures) (47)(48)(49)(50)(51)(52)(53)(54)(55)(56)(57)(58)(59)(60). Examples are the CdSe core, coated with ZnS or CdS; HgS core, coated with CdS (53); InAs coated with GaAs (61); and PbSe coated with PbS (62).…”

Section: Introductionmentioning

confidence: 96%

Optically Detected Magnetic Resonance Studies of Colloidal Semiconductor Nanocrystals

Lifshitz

Fradkin

Glozman

et al. 2004

Annu. Rev. Phys. Chem.

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The review describes the studies of the magneto-optical properties of II-VI and III-V semiconductor nanocrystals (NCs) capped with organic or inorganic epitaxial shells. The investigations focused on the chemical identification of localization sites (core, shell, or interface) of photogenerated carriers in spherical NCs and elucidated the influence of the surface/interface quality on the optical properties of the materials. Optically detected magnetic resonance (ODMR) spectroscopy was used for the study of the proposed physical properties. The ODMR method provides the means to identify the surface/interface sites and correlate them with specific optical transition. In addition, this method reveals information about the spin multiplicity of band edge and trapped states and the electron-hole exchange interaction, determines the spectroscopic g-factors, distinguishes between the radiative and nonradiative characteristic of a trapping site, and evaluates the spin-lattice relaxation times.

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Section: Introductionmentioning

confidence: 96%

Optically Detected Magnetic Resonance Studies of Colloidal Semiconductor Nanocrystals

Lifshitz

Fradkin

Glozman

et al. 2004

Annu. Rev. Phys. Chem.

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“…11,[14][15][16][17][18][19][20][21][22] The self-organized Stranski-Krastanow growth method, 23 which is well established for the In(Ga)As/ GaAs material system, 1 results for the CdSe/ZnSe system in the formation of islands with a diameter being typically larger than 30 nm. e.g., 15 Such II-VI islands are, however, too large compared to the exciton Bohr-radius of some 10Å to provide significant quantization.…”

Section: Introductionmentioning

confidence: 99%

Three-dimensionally confined excitons and biexcitons in submonolayer-CdSe/ZnSe superlattices

Straussburg

Heitz

Türck

et al. 1999

Journal of Elec Materi

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“…Evidently, these differences are associated with quantumsize effects. Moreover, several recent reports have described the development of coreshell type structures [2] in which an internal semiconductor nanocrystal is coated with an epitaxial layer of a different semiconductor. These structures have shown improvements in photoluminescence (PL) quantum yields and photo-oxidative stability, as compared with the core nanocrystals.…”

mentioning

confidence: 99%

Optically Detected Spin and Orbit Resonance of Semiconductor Quantum Dots

Lifshitz

Glozman

2001

phys. stat. sol. (b)

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The luminescence spectrum of CdSe/CdS core-shell nanocrystals contains a dominant exciton band located at the CdSe core and an additional weak non-excitonic band, associated with trapped carriers. The present paper describes our efforts to identify the influence of CdSe/CdS interfaces on the localization of photogenerated species, utilizing optically detected magnetic spin and spinorbit resonance spectroscopy (ODMR). The spin resonance (SR) spectrum showed two resonance signals: the first associated with a trapped hole in a symmetric site within the core, and a second, corresponding to trapped electrons in an anisotropic interface defect site. The spin-orbit resonance (SOR) signal data are presented. IntroductionNearly two decades of research have explored the benefits of the optical and opto-electronic properties of semiconductor nanocrystals [1]. These materials exhibit unique chemical and physical properties, differing substantially from those of the corresponding bulk solids. Evidently, these differences are associated with quantumsize effects. Moreover, several recent reports have described the development of coreshell type structures [2] in which an internal semiconductor nanocrystal is coated with an epitaxial layer of a different semiconductor. These structures have shown improvements in photoluminescence (PL) quantum yields and photo-oxidative stability, as compared with the core nanocrystals. For instance, the wide band gap (2.5 eV) of CdS and narrower band gap of CdSe (1.8 eV), cause a localization of electron and hole states within the CdSe core, in a similar manner to that of a quantum well structure. While the excitonic transitions in the CdSe/CdS core-shell samples have been investigated in the last few years [3], the understanding of interface influences on the optical properties has been neglected. Indeed, for crystals in such a small size regime, a large percentage of atoms is on/near the internal interfaces or the external surfaces. These sites may act as electron and hole traps. Thus, the present work describes our attempts to clarify the optical properties associated with trapped carriers.

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Electronic states and optical gain in strained CdS/ZnS quantum structures

Cited by 50 publications

References 8 publications

Optically Detected Magnetic Resonance Studies of Colloidal Semiconductor Nanocrystals

Optically Detected Magnetic Resonance Studies of Colloidal Semiconductor Nanocrystals

Three-dimensionally confined excitons and biexcitons in submonolayer-CdSe/ZnSe superlattices

Optically Detected Spin and Orbit Resonance of Semiconductor Quantum Dots

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