Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9812421 | Thin Solid Films | 2005 | 4 Pages |
Abstract
Carrier transport properties in amorphous oxide semiconductor InGaZnO4 (a-IGZO) thin films were investigated in detail using temperature dependence of Hall measurements. It was found that Hall mobility increased distinctly as carrier concentration increased. Unlikely conventional amorphous semiconductors such as a-Si/H, definite normal Hall voltage signals were observed on the films with carrier concentrations (Ne)>1016 cmâ3, and Hall mobilities as large as 15 cm2 (Vs)â1 were attained in the films with Ne>1020 cmâ3. When Ne was less than 1019 cmâ3, the temperature dependence of Hall mobility showed thermally-activated behavior in spite that carrier concentration was independent of temperature. While, it changed to almost degenerate conduction at Ne>1018 cmâ3. These behaviors are similar to those observed in single-crystalline IGZO, and are explained by percolation conduction through distributed potential barriers which are formed in the vicinity of the conduction band bottom due to the randomness of the amorphous structure. The effective mass of a-IGZO was estimated to be â¼0.34 me (me is the mass of free electron) from optical data, which is almost the same as that of crystalline IGZO (â¼0.32 me).
Related Topics
Physical Sciences and Engineering
Materials Science
Nanotechnology
Authors
Akihiro Takagi, Kenji Nomura, Hiromichi Ohta, Hiroshi Yanagi, Toshio Kamiya, Masahiro Hirano, Hideo Hosono,