Effect of trap-assisted tunneling on off-current property of a-InGaZnO thin-film transistors

Jihwan Park, Do Kyung Kim, Jun Ik Park, Jaehoon Park, Philippe Lang, Muhan Choi, Hyeok Kim, Jin Hyuk Bae

Research output: Contribution to journalArticlepeer-review


We describe how the off-state current (Ioff) property of amorphous InGaZnO (a-IGZO) thin-film transistors is caused by trap-assisted tunneling (TAT) by using a two-dimensional device simulation software application (Atlas 2 D, Silvaco). We found that Ioff can be increased by controlling the bandgap energy (EG) and the effective mass of electron (me) of a-IGZO transistors. When me was increased from 0.32 to 0.38 mo (mass of a free electron), the point at which Ioff started to increase in the region of negative gate voltage (VGS) shifted from −4.7 to −7.4 V. In addition, when EG was changed from 3.05 to 3.2 eV, the average value of Ioff changed from 3.13 × 10−13 to 2.4 × 10−14 A. This implies that EG and me influence the increase in Ioff in a-IGZO TFTs because of the difficulty associated with TAT.

Original languageEnglish
Pages (from-to)1-6
Number of pages6
JournalMolecular Crystals and Liquid Crystals
Issue number1
StatePublished - 2 Jul 2020


  • Off-current
  • simulation
  • thin-film transistors
  • trap-assisted tunneling


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