Subgap states in transparent amorphous oxide semiconductor, In-Ga-Zn-O, observed by bulk sensitive x-ray photoelectron spectroscopy

被引：264

作者：

Nomura, Kenji ^{[1
]}

Kamiya, Toshio ^{[1
,2
]}

Yanagi, Hiroshi ^{[2
]}

Ikenaga, Eiji ^{[3
]}

Yang, Ke ^{[3
]}

Kobayashi, Keisuke ^{[4
]}

Hirano, Masahiro ^{[1
,5
]}

Hosono, Hideo ^{[1
,2
,5
]}

机构：

[1] Tokyo Inst Technol, ERATO, SORST, JST,Frontier Res Ctr,Midori Ku, Yokohama, Kanagawa 2268503, Japan

[2] Tokyo Inst Technol, Mat Struct Lab, Midori Ku, Yokohama, Kanagawa 2268503, Japan

[3] Japan Synchrotron Radiat Res Inst, SPring 8, Mikazuki, Hyogo 6795198, Japan

[4] Natl Inst Mat Sci, SPring 8, Beamline Stn, Mikazuki, Hyogo 6795198, Japan

[5] Tokyo Inst Technol, Frontier Res Ctr, Midori Ku, Yokohama, Kanagawa 2268503, Japan

来源：

APPLIED PHYSICS LETTERS | 2008年 / 92卷 / 20期

关键词：

D O I：

10.1063/1.2927306

中图分类号：

O59 [应用物理学];

学科分类号：

摘要：

We investigated the electronic states in amorphous In-Ga-Zn-O films with high carrier concentrations by optical absorption and hard x-ray photoelectron spectroscopy (HX-PES). Films having different Hall mobilities were prepared and their annealing effects were examined. All HX-PES spectra showed Fermi edge structures and extra subgap densities of states (DOSs). Tail-like structures observed in the optical spectra originate from subgap DOSs (>> 10(20) cm(-3)) near valence band maximas (VBMs). Subgap DOSs near VBMs provide a reason why In-Ga-Zn-O thin film transistors show hard saturation in off states and are difficult to operate in an inversion p-channel mode. (C) 2008 American Institute of Physics.

引用

页数：3

共 14 条

[1]

Ashcroft N W., 1976, Solid State Physics

[2]

EPAPS, EAPPLAB92097819 EPAP

[3] Novel oxide amorphous semiconductors: Transparent conducting amorphous oxides [J].