| Autor: |
Naoya Okada, Noriyuki Uchida, Toshihiko Kanayama |
| Předmět: |
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| Zdroj: |
Journal of Applied Physics; 2015, Vol. 117 Issue 9, p095302-1-095302-7, 7p, 3 Diagrams, 1 Chart, 9 Graphs |
| Abstrakt: |
We investigated the electrical properties and derived the energy band structures of amorphous Si-rich W silicide (a-WSin) films and approximately 1-nm-thick crystalline WSin epitaxial films (e-WSin) on Si (100) substrates with composition n=8-10, both composed of Sin clusters each of which encapsulates a W atom (WSin clusters). The effect of annealing in the temperature range of 300-500 °C was also investigated. The Hall measurements at room temperature revealed that a-WSin is a nearly intrinsic semiconductor, whereas e-WSin is an n-type semiconductor with electron mobility of ~8 cm2/V s and high sheet electron density of ~7×1012cm-2. According to the temperature dependence of the electrical properties, a-WSin has a mobility gap of ~0.1 eV and mid gap states in the region of 1019cm-3 eV-1 in an optical gap of ~0.6 eV with considerable band tail states; e-WSin has a donor level of ~0.1 eV with sheet density in the region of 1012cm-2 in a band gap of ~0.3 eV. These semiconducting band structures are primarily attributed to the open band-gap properties of the constituting WSin cluster. In a-WSin, the random network of the clusters generates the band tail states, and the formation of Si dangling bonds results in the generation of mid gap states; in e-WSin, the original cluster structure is highly distorted to accommodate the Si lattice, resulting in the formation of intrinsic defects responsible for the donor level. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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