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Pietra F, De Trizio L, Hoekstra AW, Renaud N, Prato M, Grozema FC, Baesjou PJ, Koole R, Manna L, Houtepen AJ. Tuning the Lattice Parameter of InxZnyP for Highly Luminescent Lattice-Matched Core/Shell Quantum Dots. ACS Nano 2016; 10:4754-62. [PMID: 27065247 DOI: 10.1021/acsnano.6b01266] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Colloidal quantum dots (QDs) show great promise as LED phosphors due to their tunable narrow-band emission and ability to produce high-quality white light. Currently, the most suitable QDs for lighting applications are based on cadmium, which presents a toxicity problem for consumer applications. The most promising cadmium-free candidate QDs are based on InP, but their quality lags much behind that of cadmium based QDs. This is not only because the synthesis of InP QDs is more challenging than that of Cd-based QDs, but also because the large lattice parameter of InP makes it difficult to grow an epitaxial, defect-free shell on top of such material. Here, we propose a viable approach to overcome this problem by alloying InP nanocrystals with Zn(2+) ions, which enables the synthesis of InxZnyP alloy QDs having lattice constant that can be tuned from 5.93 Å (pure InP QDs) down to 5.39 Å by simply varying the concentration of the Zn precursor. This lattice engineering allows for subsequent strain-free, epitaxial growth of a ZnSezS1-z shell with lattice parameters matching that of the core. We demonstrate, for a wide range of core and shell compositions (i.e., varying x, y, and z), that the photoluminescence quantum yield is maximal (up to 60%) when lattice mismatch is minimal.
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Affiliation(s)
- Francesca Pietra
- Optoelectronic Materials Section, Faculty of Applied Sciences, Delft University of Technology , Julianalaan 136, 2628 BL Delft, The Netherlands
| | - Luca De Trizio
- Department of Nanochemistry, Istituto Italiano di Tecnologia (IIT) , via Morego, 30, 16163 Genova, Italy
| | - Anne W Hoekstra
- Optoelectronic Materials Section, Faculty of Applied Sciences, Delft University of Technology , Julianalaan 136, 2628 BL Delft, The Netherlands
| | - Nicolas Renaud
- Optoelectronic Materials Section, Faculty of Applied Sciences, Delft University of Technology , Julianalaan 136, 2628 BL Delft, The Netherlands
| | - Mirko Prato
- Department of Nanochemistry, Istituto Italiano di Tecnologia (IIT) , via Morego, 30, 16163 Genova, Italy
| | - Ferdinand C Grozema
- Optoelectronic Materials Section, Faculty of Applied Sciences, Delft University of Technology , Julianalaan 136, 2628 BL Delft, The Netherlands
| | - Patrick J Baesjou
- Philips Research Laboratories , High Tech Campus 4, 5656 AE Eindhoven, The Netherlands
- Soft Condensed Matter, Debye Institute, Utrecht University , Princetonplein 5, 3584 CC Utrecht, The Netherlands
| | - Rolf Koole
- Philips Research Laboratories , High Tech Campus 4, 5656 AE Eindhoven, The Netherlands
| | - Liberato Manna
- Department of Nanochemistry, Istituto Italiano di Tecnologia (IIT) , via Morego, 30, 16163 Genova, Italy
- Kavli Institute of Nanoscience, Delft University of Technology , Lorentzweg 1, 2628 CJ Delft, The Netherlands
| | - Arjan J Houtepen
- Optoelectronic Materials Section, Faculty of Applied Sciences, Delft University of Technology , Julianalaan 136, 2628 BL Delft, The Netherlands
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Brehm M, Grydlik M, Hackl F, Lausecker E, Fromherz T, Bauer G. Excitation Intensity Driven PL Shifts of SiGe Islands on Patterned and Planar Si(001) Substrates: Evidence for Ge-rich Dots in Islands. Nanoscale Res Lett 2010; 5:1868-72. [PMID: 21170407 PMCID: PMC2991224 DOI: 10.1007/s11671-010-9713-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2010] [Accepted: 07/19/2010] [Indexed: 05/11/2023]
Abstract
For randomly nucleated SiGe/Si(001) islands, a significantly stronger blue-shift of the PL spectra as a function of the excitation intensity is observed when compared to islands grown on patterned substrates side by side within the same run in a solid source molecular beam epitaxy chamber. We ascribe this different PL behavior to the much larger inhomogeneity of the Ge distribution in islands on planar substrates when compared to islands grown on pit-patterned ones, as observed previously. 3D band-structure calculations show that Ge-rich inclusions of approximately 5 nm diameter at the apex of the islands can account for the observed differences in the PL spectra. The existence of such inclusions can be regarded as a quantum dot in an island and is in agreement with recent nano-tomography experiments.
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Affiliation(s)
- M Brehm
- Institute of Semiconductor and Solid State Physics, University of Linz, Altenbergerstrasse 69, 4040, Linz, Austria
| | - M Grydlik
- Institute of Semiconductor and Solid State Physics, University of Linz, Altenbergerstrasse 69, 4040, Linz, Austria
| | - F Hackl
- Institute of Semiconductor and Solid State Physics, University of Linz, Altenbergerstrasse 69, 4040, Linz, Austria
| | - E Lausecker
- Institute of Semiconductor and Solid State Physics, University of Linz, Altenbergerstrasse 69, 4040, Linz, Austria
| | - T Fromherz
- Institute of Semiconductor and Solid State Physics, University of Linz, Altenbergerstrasse 69, 4040, Linz, Austria
| | - G Bauer
- Institute of Semiconductor and Solid State Physics, University of Linz, Altenbergerstrasse 69, 4040, Linz, Austria
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