| 1. |
- Willander, Magnus, 1948, et al.
(author)
-
Fundamentals and properties of zinc oxide nanostructures: optical and sensing applications
- 2008
-
In: Superlattices and Microstructures. - : Elsevier BV. - 0749-6036 .- 1096-3677. ; 43:4, s. 352-61
-
Journal article (peer-reviewed)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.
|
|
| 2. |
|
|
| 3. |
- Willander, Magnus, 1948, et al.
(author)
-
Solid and soft nanostructured materials: fundamentals and applications
- 2005
-
In: Microelectronics Journal. - : Elsevier BV. - 0026-2692. ; 36:11, s. 940-949
-
Journal article (peer-reviewed)abstract
- The scientific work worldwide on nanostructured materials is extensive as well as the work on the applications of nanostructured materials. We will review quasi two-, one- and zero-dimensional solid and soft materials and their applications. We will restrict ourselves to a few examples from partly fundamental aspects and partly from application aspects. We will start with trapping of excitons in semiconductor nanostructures. The subjects are: physical realizations, phase diagrams, traps, local density approximations, and mesoscopic condensates. From these fundamental questions in solid nanomaterials we will move to trapping of molecules in water using nanostructured electrodes. We will also discuss how to manipulate water (create vortices) by nanostructure materials. The second part deals with nanorods (nano-wires). Particularly we will exemplify with ZnO nanorods. The reason for this is that ZnO has: a very strong excitons binding energy (60 meV) and strong photon–excitons coupling energy, a strong tendency to create nanostructures, and properties which make the material of interest for both optoelectronics and for medical applications. We start with the growth of crystalline ZnO nanorods on different substrates, both crystalline (silicon, silicon carbide, sapphire, etc) and amorphous substrates (silicon dioxide, plastic materials, etc) for temperatures from 50 °C up to 900 °C. The optical properties and crystalline properties of the nanorods will be analyzed. Applications from optoelectronics (lasers, LEDs, lamps, and detectors) are analyzed and also medical applications like photodynamic cancer therapy are taken up. The third part deals with nano-particles in ZnO for sun screening. Skin cancer due to the exposure from the sun can be prevented by ZnO particles in a paste put on the exposed skin.
|
|
| 4. |
- Willander, Magnus, et al.
(author)
-
Some silicon-based heterostructures for optical applications
- 2005
-
In: Journal of Electronic Materials. - : Springer Science Business Media. - 0361-5235 .- 1543-186X. ; 34:5, s. 515-521
-
Journal article (peer-reviewed)abstract
- In this paper, we will present our recent research on the growth and characterization of some Si-based heterostructures for optical and photonic devices. The heterostructures to be discussed are ZnO nanorods on Si, SiO2, and other substrates such as SiN and sapphire. We will also consider strained Si1-xGex/Si heterostructures for Si optoelectronics. The performance and functionality extension of Si technology for photonic applications due to the development of such heterostructures will be presented. We will focus on the results of structural and optical characterization in relation to device properties. The structural characterization includes x-ray diffraction for assessment of the crystallinity and stress in the films and secondary ion mass spectrometry for chemical analysis. The optical properties and electronic structure were investigated by using photoluminescence. The device application of these thin film structures includes detectors, lasers, and light emitting devices. Some of the Si-based heterostructures to be presented include devices emitting and detecting up to the blue-green and violet wave lengths.
|
|
