Symmetry and electronic structure of the Mn impurity in ZnS nanocrystals

Kennedy, T. A.; Glaser, E. R.; Klein, P. B.; Bhargava, R. N.

doi:10.1103/physrevb.52.r14356

Cited by 174 publications

(159 citation statements)

References 5 publications

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“…12 The crystal-field experienced by the Mn impurities will depend on the location of Mn in the host quantum dots. Also the crystal-field experienced by Mn impurities near the nanocrystal surface 11 will be significantly different from that of the bulk material. EPR measurements can give insight to the local crystal-field effects and symmetry around the Mn ions.…”

Section: Resultsmentioning

confidence: 99%

“…Moreover, at least in some of the quantum dots, the Mn-Mn interaction is strong enough to reveal the hyperfine splitting. Signal II may arise due to the location of Mn near the surface 5,11,13 of the ZnSe quantum dot. Signal II is superimposed on signal I, and is originated since Mn 2+ has less of a symmetric environment.…”

Section: Resultsmentioning

confidence: 99%

“…1 Moreover, the number of Mn ions incorporated at substitutional sites can also modify the lattice parameters as well as the band gap of semiconducting materials. Additionally, the Mn-related electron paramagnetic resonance ͑EPR͒ signal is strong 3,5,11 in the ternary compounds and has been modeled for various chemical environments. However, the large variations in magnetic properties of doped quantum dots have been reported, and the role of the synthesis route in chemically controlled magnetic effects has been identified.…”

Section: Introductionmentioning

confidence: 99%

“…2 High fluorescence efficiency along with magnetic ordering makes Mn an interesting transition element dopant [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] in the semiconductor nanoparticles. Recently, Mn-doped ZnSe nanoparticles [3][4][5][6][7][8][9][10] received much attention since it has the potential application for luminescent as well as spintronic devices.…”

Section: Introductionmentioning

confidence: 99%

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Magnetic behavior of manganese-doped ZnSe quantum dots

Lad

Rajesh

Khan

et al. 2007

Journal of Applied Physics

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Magnetic properties of manganese-doped ZnSe quantum dots with the size of approximately 3.6 nm are investigated. The amount of Mn in the ZnSe quantum dots has been varied from 0.10% to 1.33%. The doping level in the quantum dots is much less than that used in the precursor. The co-ordination of Mn in the ZnSe lattice has been determined by electron paramagnetic resonance ͑EPR͒. Two different hyperfine couplings 67.3ϫ 10 −4 and 60.9ϫ 10 −4 cm −1 observed in the EPR spectrum imply that Mn atoms occupy two distinct sites; one uncoordinated ͑near the surface͒ and other having a cubic symmetric environment ͑nanocrystal core͒, respectively. Photoluminescence measurements also confirm the incorporation of Mn in ZnSe quantum dots. From the Curie-Weiss behavior of the susceptibility, the effective Mn-Mn antiferromagnetic exchange constant ͑J 1 ͒ has been evaluated. The spin-glass behavior is observed in 1.33% Mn-doped ZnSe quantum dots, at low temperature. Magnetic behavior at a low temperature is discussed.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Magnetic behavior of manganese-doped ZnSe quantum dots

Lad

Rajesh

Khan

et al. 2007

Journal of Applied Physics

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“…Since the hyperfine splitting is strongly dependent on the local environment, EPR spectra can be used to determine the location of the Mn. 23 From Figure 4a, we extract a hyperfine splitting of 60.4 × 10 -4 cm -1 . This value agrees well with that obtained for Mn at cubic lattice sites in bulk ZnSe (61.7 Figure 1).…”

Section: Report Documentation Pagementioning

confidence: 99%

High-Quality Manganese-Doped ZnSe Nanocrystals

Norris¹,

et al. 2000

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We demonstrate high-quality, highly fluorescent, ZnSe colloidal nanocrystals (or quantum dots) that are doped with paramagnetic Mn 2+ impurities. We present luminescence, magnetic circular dichroism (MCD), and electron paramagnetic resonance (EPR) measurements to confirm that the Mn impurities are embedded inside the nanocrystal. Optical measurements show that by exciting the nanocrystal, efficient emission from Mn is obtained, with a quantum yield of 22% at 295 K and 75% below 50 K (relative to Stilbene 420). MCD spectra reveal an experimental Zeeman splitting in the first excited state that is large (28 meV at 2.5 T), depends on doping concentration, and saturates at modest fields. In the low field limit, the magnitude of the effective g factor is 430 times larger than in undoped nanocrystals. EPR experiments exhibit a six-line spectrum with a hyperfine splitting of 60.4 × 10 -4 cm -1 , consistent with Mn substituted at Zn sites in the cubic ZnSe lattice.Nanometer-scale semiconductor crystallites, also referred to as nanocrystals or quantum dots, have been extensively studied to explore their unique properties and potential applications. 1 Interesting behavior arises in these materials due to the confinement of optically excited electron-hole pairs by the crystallite boundary. However, while the basic explanation of this phenomenon, known as the quantum size effect, was provided early in the investigation of these materials, 2-4 a detailed understanding required the advent of high-quality colloidal nanocrystals, which were uniform in size, shape, crystallinity, and surface passivation. Once such materials became available, 5 tremendous progress was made in a variety of physical studies. Consequently, many of the properties of semiconductor nanocrystals are now understood in detail. 1 In addition, high-quality crystallites have led to more complicated nanocrystal-based structures, such as quantum-dot solids, 6 light-emitting devices, 7 and even photonic crystals. 8 These successes have encouraged researchers to go beyond pure nanocrystals and investigate particles that are intention-*

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