Solution-processed Li-doped ZnSnO metal-semiconductor-metal UV photodetectors

Abstract

The electrical performance of thin-film transistors that use an amorphous oxide semiconductor (AOS) is significantly improved by incorporating metal cations as carrier suppressors. However, the effect of these elements on the performance of AOS-based photodetectors (PDs) is still unknown. This study uses a precursor containing lithium (Li) element and a sol-gel process to produce a Li-doped amorphous ZnSnO (a-ZTO) thin-film for UV PD applications. The results of x-ray photoelectron spectroscopy analysis show that the number of oxygen vacancies (V o) in a-ZTO thin-films decreases significantly from ∼32.1% to ∼14.4% after Li-doping (3 at%). The dark current decreases and the photocurrent increases in the ZTO-based PD so an ultra-high photo-to-dark current ratio (PDCR) of 1185 is achieved. The significant increase in PDCR means that solution-processed a-ZTO are eminently suited to use in UV PDs that use In-free AOSs.

Low-Temperature Solution-Processed ZnSnO Ozone Gas Sensors Using UV-Assisted Thermal Annealing

“…The peak with a higher binding energy component at 531.6 eV is attributed to oxygen vacancies (V o ). 20 In Figs. 5a and 5b, the V o area ratio decreases from 0.343 (UVTA-30) to 0.192 (UVTA-120), which demonstrates that this method passivates the V o in the oxide film.…”

“…Oxygen vacancies act as donors in AOS. 20 Surface oxidization decreases the electron concentration so gas adsorption is ineffective. Selectivity is a figure of merit for gas sensors that discriminate the target if there is interference molecules.…”

“…18 Amorphous ZnSnO (a-ZTO) is a commonly occurring material that is an alternative to a-IGZO. 19,20 Few studies use a-ZTO as a gas sensing material. 21 Most AOSs are deposited using complicated physical vapor deposition, such as sputtering 22 or pulsed laser deposition, 23 but these methods require a vacuum system so manufacturing costs are greater.…”

Implementation of Synaptic Device Using Ultraviolet Ozone Treated Water‐in‐Bisalt/Polymer Electrolyte‐Gated Transistor

“…The Li 1s spectrum is divided into two peaks, attributed to the interstitial defects and LiO bonds at 54.9 and 55.7 eV, respectively. [40,41] These peaks are detected on the UVO-treated IGZO surface (w/UVO), which are not detected in the untreated IGZO, indicating that residual lithium atoms remain on the surface of UVO-treated WEST (Figure S3, Supporting information). [42]…”

Increasing the Gas Response of Ozone Sensors Based on Solution-Processed InGaZnO by Tuning the Size of the Nanostructure

“…25 Amorphous oxide semiconductors (AOSs), such as amorphous InZnO (a-IZO), 26 amorphous GaZnO (a-GZO), 27 amorphous ZnSnO (a-ZTO) 28 and amorphous InGaZnO (a-IGZO), 29 are used for a wide range of applications in electronics and optoelectronic devices because they feature high visible transparency, high carrier mobility, low cost and low processing temperature. 30,31 The most common AOS is a-IGZO. 32 Thin-film transistors (TFTs) that use a-IGZO are a replacement for those that use amorphous Si (a-Si) TFTs.…”