Sharp photoluminescence of CdS nanocrystals in Al2O3 matrices formed by sequential ion implantation

Ando, M.; Kanemitsu, Yoshihiko; Kushida, Takashi; Matsuda, Kazunari; Saiki, Takanao; White, C. W.

doi:10.1063/1.1387259

Cited by 23 publications

(21 citation statements)

References 14 publications

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“…At low temperatures, the broad PL band appears at the energy region below the free-exciton absorption edge [7]. From detailed spectral analyses it is concluded that the broad PL band is due to radiative recombination of excitons bound to impurities in CdS nanocrystals [7,10]. On the contrary, a sharp PL line is observed in the SNOM-PL spectrum (Fig.…”

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confidence: 75%

Photoluminescence Spectra and Dynamics of Single CdS Nanocrystals Studied by Scanning Near-Field Optical Microscopy

Kanemitsu

Ando

Matsuda

et al. 2002

phys. stat. sol. (a)

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Photoluminescence (PL) spectra and dynamics of hexagonal CdS nanocrystals embedded in Al 2 O 3 matrices have been studied by means of a scanning near-field optical microscope at 8 K. The PL spectra of individual CdS nanocrystals show narrow lines with single-exponential decay profiles, although the macroscopic PL spectra measured by conventional optics show a broad band with non-exponential decay profiles. The PL peaks are observed at energies below the lowest freeexciton energy of CdS nanocrystals. The luminescence mechanism of CdS nanocrystals is discussed.Introduction Recently, semiconductor nanocrystals have attracted much attention because of their unique physical properties and their potential use in a wide range of applications [1]. Many techniques have been developed to synthesize high-quality semiconductor nanocrystals. One of the most versatile techniques for creating nanocrystals embedded in dielectric matrices is ion implantation followed by thermal annealing [2]. The embedded nanocrystal structures have several advantages, such as chemical and mechanical stability. In addition, it has been successfully demonstrated that compound semiconductor nanocrystals can be simply fabricated by sequential ion implantation of the elements forming the compound [2-6]. A disadvantage is the relatively wide size distribution of the created nanocrystals. Therefore, optical characterization with a high spatial resolution is important for the understanding of the optical properties of nanocrystal/matrix composite systems. In the work reported here, we fabricated CdS nanocrystals embedded in Al 2 O 3 matrices by ion beam synthesis and studied the photoluminescence (PL) properties of individual CdS nanocrystals by means of a scanning nearfield optical microscope (SNOM).

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confidence: 75%

Photoluminescence Spectra and Dynamics of Single CdS Nanocrystals Studied by Scanning Near-Field Optical Microscopy

Kanemitsu

Ando

Matsuda

et al. 2002

phys. stat. sol. (a)

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“…The second peak exists in the L band, noticeable at 1.76 eV (λ ∼ 706 nm) and corresponds to radiative recombination associated with deep trap states. It has been reported by Ando, et al that the broad PL bands consist of sharp lines of various luminescence energies [5]. They attributed the lines to radiative recombination of excitons and carriers localized to defects in the nanocrystals.…”

Section: Oxygen Ion Irradiationmentioning

confidence: 99%

“…There are numerous reports available in the literature with regard to optical, electrical and luminescence properties of II-VI semiconducting materials [3][4][5]. Semiconductor nanoparticles embedded in glass or in polymer dielectric hosts are interesting for their optical quality and long term stability [5][6][7][8]. A typical embedded nanoparticle system is different from nanostructured films in view of the presence of isolated nanoparticles where the grain boundary problem is nonobvious, which is otherwise observable in nanostructured materials.…”

Section: Introductionmentioning

confidence: 99%

“…In recent years, research in nanoscaled materials has gained growing interest due to dimension dependent tunable electronic energy levels, finding technological importance in photonics and nonlinear optics [1,2]. There are numerous reports available in the literature with regard to optical, electrical and luminescence properties of II-VI semiconducting materials [3][4][5]. Semiconductor nanoparticles embedded in glass or in polymer dielectric hosts are interesting for their optical quality and long term stability [5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

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Influence of ion bombardment on the photoluminescence response of embedded CdS nanoparticles

et al. 2006

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Semiconductor nanoparticles (CdS) were fabricated by an inexpensive chemical route using polyvinyl alcohol (PVA) as the dielectric host matrix. Nano-CdS in PVA were subjected to ion irradiation (using oxygen, chlorine and gold) in the medium energy range (80-100 MeV) and under fluence variation of 10 11 − 10 13 ions/cm 2 . The nature of light emission was found to be drastically different in each of the three cases. Photoluminescence spectra of oxygen irradiated samples exhibit band edge emission (2.8 eV) as well as trap related emission (1.76 eV) whereas band edge emission is found to be bleached out for chlorine ion irradiated nano-CdS. The intense broad PL peaks, noticeable in the case of gold ion irradiated samples suggest superposition of the two peaks -namely, band edge emission and trap related emission. Furthermore, in the case of gold ion irradiated nano-CdS, energy shift in the PL spectra reveals variation in size distribution caused by the extra pressure effect of heavy gold ion beams. The mechanism of such a difference as a result of ion irradiation-type and ion-fluence is discussed in detail.

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“…This PL is nearly independent of particle size, suggesting the influence of defects. Using scanning near-field optical microscopy (SNOM), twodimensional luminescence images of CdS nanoclusters in Al 2 O 3 have been obtained [71]. These images show randomly distributed bright regions attributed to the presence of CdS nanocrystals.…”

Section: Light-emitting Materialsmentioning

confidence: 99%

Structure and Properties of Nanoparticles Formed by Ion Implantation

Meldrum

López

Magruder

et al. 2009

Topics in Applied Physics

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Abstract. This chapter broadly describes the formation, basic microstructure, and fundamental optoelectronic properties of nanocomposites synthesized by ion implantation. It is not meant as a complete literature survey and by no means includes all references on a subject that has seen a considerable amount of research effort in the past 15 years. However, it should be a good starting point for those new to the field and in a concise way summarize the main lines of research by discussing the optical, magnetic, and "smart" properties of these nanoparticles and the dependence of these properties on the overall microstructure. The chapter concludes with an outlook for the future.

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Sharp photoluminescence of CdS nanocrystals in Al2O3 matrices formed by sequential ion implantation

Cited by 23 publications

References 14 publications

Photoluminescence Spectra and Dynamics of Single CdS Nanocrystals Studied by Scanning Near-Field Optical Microscopy

Photoluminescence Spectra and Dynamics of Single CdS Nanocrystals Studied by Scanning Near-Field Optical Microscopy

Influence of ion bombardment on the photoluminescence response of embedded CdS nanoparticles

Structure and Properties of Nanoparticles Formed by Ion Implantation

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