Investigation to the Carrier Transport Properties in Heterojunction-Channel Amorphous Oxides Thin-Film Transistors Using Dual-Gate Bias

The carrier transport properties in amorphous oxide semiconductor (AOS) heterojunction thin-film transistors (TFTs) are investigated by using dual gates to control the channel of bilayer AOSs. The mobility of such heterojunction channel exhibited distinct dependences on top-gate (TG) voltage (V-TG) and bottom-gate (BG) voltage (V-BG) The mobility was well maintained in TG mode, where V-TG was in line with the build-in electric field of the electron potential well (PW) formed at the heterojunction interface. In contrast, an increased V-BG gradually reduced the high mobility to the level of a single layer channel, since a high V-BG in the opposite direction of PW could eliminate the PW. This experimentally clarifies that the high-mobility transport path of AOS heterojunction channel locates in the interface PW and its operation demands a proper gate field direction. This were directly consolidated by the disclosed unique capacitance-voltage characteristics.

Automated summary

The carrier transport properties in amorphous oxide semiconductor (AOS) heterojunction thin-film transistors (TFTs) were investigated using dual gates to control the channel of bilayer AOSs. The mobility of the heterojunction channel depended on both the top-gate (TG) voltage (V-TG) and the bottom-gate (BG) voltage (V-BG). The high mobility of the AOS heterojunction channel was maintained in TG mode, but decreased with increased V-BG, indicating the importance of the gate field direction.