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Polymer Doping Enables a Two‐Dimensional Electron Gas for High‐Performance Homojunction Oxide Thin‐Film Transistors
Author(s) -
Chen Yao,
Huang Wei,
Sangwan Vinod K.,
Wang Binghao,
Zeng Li,
Wang Gang,
Huang Yan,
Lu Zhiyun,
Bedzyk Michael J.,
Hersam Mark C.,
Marks Tobin J.,
Facchetti Antonio
Publication year - 2019
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.201805082
Subject(s) - homojunction , materials science , optoelectronics , thin film transistor , doping , oxide , work function , indium , dielectric , band offset , electron mobility , nanotechnology , analytical chemistry (journal) , layer (electronics) , band gap , metallurgy , valence band , chemistry , chromatography
High‐performance solution‐processed metal oxide (MO) thin‐film transistors (TFTs) are realized by fabricating a homojunction of indium oxide (In 2 O 3 ) and polyethylenimine (PEI)‐doped In 2 O 3 (In 2 O 3 : x % PEI, x = 0.5–4.0 wt%) as the channel layer. A two‐dimensional electron gas (2DEG) is thereby achieved by creating a band offset between the In 2 O 3 and PEI‐In 2 O 3 via work function tuning of the In 2 O 3 : x % PEI, from 4.00 to 3.62 eV as the PEI content is increased from 0.0 (pristine In 2 O 3 ) to 4.0 wt%, respectively. The resulting devices achieve electron mobilities greater than 10 cm 2 V −1 s −1 on a 300 nm SiO 2 gate dielectric. Importantly, these metrics exceed those of the devices composed of the pristine In 2 O 3 materials, which achieve a maximum mobility of ≈4 cm 2 V −1 s −1 . Furthermore, a mobility as high as 30 cm 2 V −1 s −1 is achieved on a high‐ k ZrO 2 dielectric in the homojunction devices. This is the first demonstration of 2DEG‐based homojunction oxide TFTs via band offset achieved by simple polymer doping of the same MO material.