Competing weak localization and weak antilocalization in amorphous indium–gallium–zinc-oxide thin-film transistors

Abstract

We have investigated the gate-voltage dependence and the temperature dependence of the magnetoconductivity of amorphous indium-gallium-zinc-oxide thin-film transistors. A weak-localization feature is observed at small magnetic fields on top of an overall negative magnetoconductivity at higher fields. An intriguing controllable competition between weak localization and weak antilocalization is observed by tuning the gate voltage or varying the temperature. Our findings reflect controllable quantum interference competition in the electron systems in amorphous indiumgallium-zinc-oxide thin-film transistors.Amorphous metal-oxide semiconductors have recently been studied for applications in thin-film transistors (TFTs) for large-area flexible electronics because of their electrical uniformity and fabrication advantage of roomtemperature deposition and patterning [1][2][3][4]. In particular, zinc oxide (ZnO) has recently attracted intense experimental and theoretical attention owing to its potential use in the emerging nanoelectronics and optoelectronics [5][6][7]. ZnO-based semiconductors can incorporate indium oxide as a carrier-mobility enhancer and gallium oxide or hafnium oxide as a columnar-structure suppressor for the amorphous phase in order to achieve high field-effect mobility and low off-state current of the channel [8][9][10]. They have become promising candidates of transparent and flexible nonvolatile memories to be integrated in system-on-panel displays [11][12][13].Aside from practical studies to achieve higher quality of amorphous indium-gallium-zinc-oxide (InGaZnO 4 ) TFTs, investigations of their fundamental electrical properties at low temperatures are necessary for studying quantum corrections to the conductivities of these carrier systems with disorders. Quantum interference and weak localization have been explored in three-dimensional and low-dimensional electron systems in various materials [14][15][16][17][18][19][20][21]. Indium zinc oxide (IZO) films and nanowires [22][23][24][25][26][27] in particular have raised special interest because of their potential applications in modern technologies. However, a comprehensive, in-depth study of lowtemperature electrical transport in IZO is still missing, and the underlying mesoscopic and microscopic mechanisms remain largely unclear. Moreover, there are few detailed studies of low-temperature transport properties of practical IZO transistor devices. Measurements of IZO * E-mail: pjiang@ntnu.edu.tw transistors at low temperatures may reveal interesting quantum-mechanical phenomena.In this work, we present a study of the drain-source channel magnetoconductivity (MC) of an amorphous InGaZnO 4 (a-IGZO) TFT measured at cryogenic temperatures. Manipulated via electric gating, the MC reveals a competition between weak localization (WL) and weak antilocalization (WAL) at small magnetic fields, where the WL component stays small but steady, while the WAL component lessens drastically with decreasing gate voltage. On the other hand, the temperature dependence...

Universal dependence on the channel conductivity of the competing weak localization and antilocalization in amorphous InGaZnO4thin-film transistors

“…A is a small coefficient of 10 −4 , which we have added to the original two-component HLN equation to adequately present the nontrivial information retrieved from the seriously suppressed conduction of a-IGZO TFTs at low temperatures. 34) Equation ( 1) provides excellent fits to the data, which are displayed as solid smooth lines in Fig. 2.…”

“…[26][27][28][29][30][31][32][33] However, few comprehensive indepth studies of the low-temperature electrical transports in InZnO and similar multicomponent oxide semiconductors were conducted. Recently, we reported an intriguing observation of controllable competition between weak localization (WL) and weak antilocalization (WAL) in the electron systems in a-IGZO TFTs under variation of the gate voltage or the temperature, 34) but the underlying mechanism remains undetermined. More studies are required to further understand the quantum interference in these systems.…”

“…Therefore, as one of the control variables, a fixed T of 30 K has been chosen for the following experiment to obtain I S with reasonable signal-tonoise ratios for all the samples, while the electron systems in a-IGZO TFTs are still kept in the quantum diffusive regime. 27,34) Typical I S -V G characteristics of an a-IGZO TFT at room temperature and at 30 K can be seen from a representative sample shown in Fig. 1.…”

A Dual‐Gate InGaZnO4‐Based Thin‐Film Transistor for High‐Sensitivity UV Detection

“…In industry, the metal oxide composition material InGaZnO 4 (IGZO) was originally proposed for display applications . Due to its high transparency, uniformity, and mobility, IGZO has significant attention for various applications and their related TFT reliability issues . In addition, IGZO has a WBG characteristic of 3.1–3.4 eV, depending on the composition ratio .…”

Drain Current Stress-Induced Instability in Amorphous InGaZnO Thin-Film Transistors with Different Active Layer Thicknesses

“…Recently, amorphous indium gallium zinc oxide (a-IGZO), as a representative of an amorphous metal oxide-based semiconductor, has been widely investigated for use in the active layer of thin-film transistors (TFTs) due to its high electron mobility, good transparency in visible light, chemical and thermal stability, low temperature processing, and smooth surface [ 1 , 2 , 3 , 4 ]. The a-IGZO TFT with excellent electrical properties, such as high mobility ( μ ) of over 10 cm 2 ·V −1 ·s −1 and low values of subthreshold swing, has become one of the research hotspots for the advanced display application in next-generation active-matrix liquid crystal displays (AM-LCDs) and active-matrix organic light-emitting diodes (AM-OLEDs) [ 5 , 6 , 7 , 8 ].…”