ISSN:
1662-9752
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Hydrogenated amorphous silicon (a-Si:H) has attracted much attention in various electronicsapplications such as thin films transistors, color sensors, and solar cells[1]. However, many devicesmade from a-S:H are observed to degrade with time, which is commonly associated with hydrogenrelated defects [1]. It has been observed that, by increasing the hydrogen dilution in the precursorgas used in the plasma, one can obtain hydrogenated nanocrystalline silicon (nc-Si:H), whichcontains crystalline grains embedded in an amorphous silicon matrix. These materials can bedeposited by plasma enhanced chemical vapor deposition (PECVD) techniques. The presence of nc-Si in a-Si:H changes the optical and electronic properties of the material [2]. Nc-Si:H thin filmshave exhibited unique and useful characteristics. In particular, nc-Si:H thin films exhibitphotoluminescence (PL) and electroluminescence (EL) behavior at room temperature [3].The dilution of SiH4 with hydrogen has been recognized as an effective method for thetransition from the amorphous to the nanocrystalline phase in the nc-Si:H thin films. The presenceof hydrogen on the growing surface gives termination of dangling bonds and also an extraction ofSiH3 radicals [4]. The supply balance between the hydrogen and SiH3 radicals is a key factor indetermining the film structure [4]. The presence of excess hydrogen or hydrogen-bonded Si radicals(SiHn = 1, 2, 3) in the gas mixture passivates the dangling bonds on the growing surface and etchesthe growing surface. Etching eliminates part of the disordered structure and enhances the crystallinephase because the crystalline structure is the lowest energy configuration.In this paper, we report the study of the effects of the hydrogen species on the nanostructuresand optical properties of nc-Si:H thin films prepared by PECVD techniques
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/08/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.449-452.1017.pdf
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