Highly stable Ba-addition InZnSnO channels of light emitting transistors and thin film transistors

Abstract

In this study, we investigate the characteristics of barium-addition indium-zinc-tin-oxide (B–IZTO) channels fabricated by the co-sputtering of barium-tin-oxide and indium-zinc-tin-oxide (IZTO) targets for the operation of thin film transistors (TFTs) and light emitting transistors (LETs). The X-ray photoelectron spectroscopy (XPS) analysis verifies that increasing the BaSnO3 sputtering power significantly decreases the concentration of oxygen vacancy from 35.0% to 16.3%. In addition, increasing the Ba concentration in the B–IZTO films increases the average transmittance of the B–IZTO channel in the visible light region (400–800 nm) from 86.7% to 88.3%, and the electrical resistivity from 84.3 to 5408 Ω∙cm, respectively. We find that the appropriate composition of Ba in the IZTO channels greatly improves the subthreshold swing (SS), the stability against the negative bias illumination stress (NBIS) of the B–IZTO channels-based TFTs. As the Ba content of the IZTO channel layer increases, SS decreases from 0.49 to 0.13 V/decade and the threshold voltage shift (ΔVTH) by NBIS reduces from − 13.1 to − 5.07 V, respectively. In the case of the B–IZTO-based LET with the highest Ba content, the device has the lowest light turn on voltage (VON) of 1.84 V, and shows the maximum brightness of 1.53 × 104 cd/m2. In this study, we confirm that the addition of Ba in the IZTO effectively suppresses the oxygen vacancies in the IZTO channel, resulting in the enhanced stability of the B–IZTO-based TFTs, and improves the performance of the B–IZTO-based LETs.