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| 2. |
- Borseth, T.M., et al.
(författare)
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Identification of oxygen and zinc vacancy optical signals in ZnO
- 2006
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 89:26, s. 262112-262115
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Tidskriftsartikel (refereegranskat)abstract
- Photoluminescence spectroscopy has been used to study single crystalline ZnO samples systematically annealed in inert, Zn-rich and O-rich atmospheres. A striking correlation is observed between the choice of annealing ambient and the position of the deep band emission (DBE) often detected in ZnO. In particular, annealing in O2 results in a DBE at 2.35±0.05 eV, whereas annealing in the presence of metallic Zn results in DBE at 2.53±0.05 eV. The authors attribute the former band to zinc vacancy (VZn) related defects and the latter to oxygen vacancy (VO) related defects. Additional confirmation for the VO and VZn peak identification comes from the observation that the effect is reversible when O- and Zn-rich annealing conditions are switched. After annealing in the presence of ZnO powder, there is no indication for the VZn- or VO-related bands, but the authors observe a low intensity yellow luminescence band peaking at 2.17 eV, probably related to Li, a common impurity in hydrothermally grown ZnO.
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| 3. |
- Chiragwandi, Zackary, 1968, et al.
(författare)
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Ultraviolet driven negative current and rectifier effect in self assembled green fluorescent protein devices
- 2006
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 89:16, s. 162909-1-162909-3
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Tidskriftsartikel (refereegranskat)abstract
- UV induced negative current produced at low voltages is reported in a photocurrent rectifier device consisting of a sensing region between two nano Al/Al2O3 electrodes placed 30 nm apart, employing a droplet of enhanced green fluorescent protein as molecular electrolyte. The current-voltage characteristics are discussed in terms of the properties of the thin Al2O3 scale, the position of the Fermi level, the position of the highest occupied molecular orbital-lowest unoccupied molecular orbital gap, and dispersion of states induced by varying dielectric constants
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| 5. |
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| 6. |
- Lu, W., et al.
(författare)
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Application of combinatorial material chip method on the improvement of quantum dots emission efficiency
- 2004
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Ingår i: Proceedings of the SPIE - The International Society for Optical Engineering. - : SPIE. - 0277-786X .- 1996-756X. ; 5277:1, s. 99-108
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Konferensbidrag (refereegranskat)abstract
- The combinatorial material chip method has been used to study the emission efficiency of InAs/GaAs quantum dots. The photoluminescence spectroscopy is performed to obtain the rule of emission efficiency on the proton implantation dose. A pronounced enhancement of room temperature emission efficiency has been obtained by the optimized quantum dots process condition. The increment of emission efficiency up to 80 itmes has been observed. This effect may be resulted from both the proton passivation and carrier capture enhancement effects. The maximum photoluminescence peak shift is about 23 meV resulted from the intermixing of quantum dots. A linear dependence behavior has been observed for both the non-radiative recombination time and carrier relaxation time on the ion-implantation dose. The maximum enhancement of the photoluminescence is observed in the proton implantation dose of 1.0 x 1014 cm-2 followed by rapid thermal annealing at 700°C. These effects will be useful for the QDs' optoelectronic devices.
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| 9. |
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| 10. |
- Willander, Magnus, 1948, et al.
(författare)
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Fundamentals and properties of zinc oxide nanostructures: optical and sensing applications
- 2008
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Ingår i: Superlattices and Microstructures. - : Elsevier BV. - 0749-6036 .- 1096-3677. ; 43:4, s. 352-61
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Tidskriftsartikel (refereegranskat)abstract
- In this paper we will give an overview of the status of catalytic growth and of low-temperature chemical growth of ZnO nanostructures performed in our laboratory. Particularly results employing different substrates will be discussed. The second part deals with structural and optical properties of ZnO nanorods. The results from high resolution transmission electron microscope (HRTEM), scanning electron microscope (SEM), photoluminescence (PL), Cathodoluminescence (CL), and Electroluminescence (EL), on single nanowires will be shown. Our results on surface morphology, bulk and the position of the catalyst as well as the optical properties including UV emission, lasing and white emission will all be presented and discussed. In the third part experimental results from electroluminescence of ZnO nanorods on different substrates in the UV in addition to excellent white light emission obtained from samples grown at low temperature are to be given and discussed. Finally the sensing of molecules in water by ZnO nanorods will be discussed from a theoretical point of view. Also fundamental properties of polaritons and excitons in ZnO nanostructures are to be highlighted.
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