Experimental and Theoretical Evidence of Charge Injection Barrier Control by Small-Molecular Charge Injection Layer and Its Effects on Organic-Inorganic Complementary Inverters

• Published in: IEEE transactions on electron devices Vol. 70; no. 4; pp. 1 - 5
• Main Authors: Han, Youngmin, Kim, Seongjae, Kim, Chang-Hyun, Yoo, Hocheon
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.04.2023; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: 2-D simulation; Charge injection; Circuits; complementary inverters; Contact resistance; Electric contacts; Electric variables; Electrodes; Gallium; Gold; Indium gallium zinc oxide; Inverters; Optical microscopy; organic semiconductors; Semiconductor devices; Thin film transistors; thin-film transistors (TFTs); Zinc oxide
• ISSN: 0018-9383; 1557-9646
• DOI: 10.1109/TED.2023.3247682

Introducing a contact charge injection layer at the interface between the contact electrode and active materials is considered crucial to obtain efficient charge injection behaviors in thin-film transistors (TFTs). Here, we investigate the effect of a small molecule contact charge injection layer through experimental results and theoretical calculations. We found limited electrical characteristics derived from contact resistance in C8-BTBT TFTs with C8-BTBT as the channel and Au as the electrode. We experimentally demonstrated that the limited electrical characteristics of C8-BTBT TFT can be improved by inserting dinaphtho2,3-b:2<inline-formula> <tex-math notation="LaTeX">^\prime</tex-math> </inline-formula>,3<inline-formula> <tex-math notation="LaTeX">^\prime</tex-math> </inline-formula>-fthieno 3,2-b thiophene (DNTT), which has a low contact resistance at the junction with Au, as a charge injection layer. The results of improved contact properties through the DNTT charge injection layer were also consistent with the results of energy structural simulations. Furthermore, we verified the effect of the DNTT charge injection layer at the circuit level through improved noise margin characteristics in the complementary inverter composed of asymmetric charge injection layer TFT (ACIL-TFT) and a-indium gallium zinc oxide (IGZO) TFT.