Abstract
The transparency of oxide semiconductors is a significant feature that enables the fabrication of fully transparent electronics. Unfortunately, practical transparent electronics using amorphous oxide semiconductors (AOSs) have not yet been realized, owing to significant photo-instabilities of these materials. Previous studies have revealed that the photo-instability can be attributed to sub-gap states (SGSs) near the valence-band maximum (VBM). Thus, it is inferred that the energy difference between the SGSs and the conduction-band minimum must be widened sufficiently in order to make it fully transparent over the entire visible-light region. In this work, we examined the electronic structures of a variety of AOSs and found that their ionization potentials vary greatly, depending upon the specific metal cations. This finding enabled us to increase the optical bandgap by modifying the VBM levels, resulting in a high mobility of 9 cm2/Vs and an ultra-wide bandgap of 3.8 eV for amorphous Zn–Ga–O (a-ZGO). We show that a-ZGO thin-film transistors exhibit no negative-bias illumination-stress instability with no passivation and no light-shielding layer.
Highlights
We examined the electronic structures of a variety of amorphous oxide semiconductors (AOSs) and found that their ionization potentials vary greatly, depending upon the specific metal cations
We recently found that amorphous Zn–Ga–O (a-ZGO) exhibits a large variation in EVBM, corresponding to ionization potential (I.P.), whereas ECBM remains almost unchanged
We investigated a-ZGO thin films and compared the energy levels of amorphous In–Zn–O (IZO) and a-ZGO using in situ ultra-violet photoemission spectroscopy (UPS)
Summary
Practical transparent electronics using amorphous oxide semiconductors (AOSs) have not yet been realized, owing to significant photo-instabilities of these materials.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.