Impact of the Cation Composition on the Electrical Performance of Solution-Processed Zinc Tin Oxide Thin-Film Transistors

Abstract

This study examined the structural, chemical, and electrical properties of solution-processed (Zn,Sn)O3 (ZTO) films with various Sn/[Zn+Sn] ratios for potential applications to large-area flat panel displays. ZTO films with a Zn-rich composition had a polycrystalline wurtzite structure. On the other hand, the Sn-rich ZTO films exhibited a rutile structure, where the Zn atom was speculated to replace the Sn site, thereby acting as an acceptor. In the intermediate composition regions (Sn/[Zn+Sn] ratio from 0.28 to 0.48), the ZTO films had an amorphous structure, even after annealing at 450 °C. The electrical transport properties and photobias stability of ZTO thin film transistors (TFTs) were also examined according to the Sn/[Zn+Sn] ratio. The optimal transport property of ZTO TFT was observed for the device with an amorphous structure at a Sn/[Zn+Sn] ratio of 0.48. The mobility, threshold voltage, subthreshold swing, and on/off current ratio were 4.3 cm(2)/(V s), 0 V, 0.4 V/decade, and 4.1 × 10(7), respectively. In contrast, the device performance for the ZTO TFTs with either a higher or lower Sn concentration suffered from low mobility and a high off-state current, respectively. The photoelectrical stress measurements showed that the photobias stability of the ZTO TFTs was improved substantially when the ZTO semiconducting films had a lower oxygen vacancy concentration and an amorphous structure. The relevant rationale is discussed based on the phototransition and subsequent migration mechanism from neutral to positively charged oxygen vacancies.

Effect of antimony doping on the low-temperature performance of solution-processed indium oxide thin film transistors

“…The C i value measured at the frequency of 1 MHz was used in the μ sat calculation. The extraction method of V th and SS value can be referred elsewhere . It is noted that the μ sat value can be overestimated due to the effect of the fringing electric field because the channel region was not patterned in this study.…”

“…The C i value measured at the frequency of 1 MHz was used in the μ sat calculation. The extraction method of V th and SS value can be referred elsewhere [14].…”

All‐Solution‐Processed Metal Oxide/Chalcogenide Hybrid Full‐Color Phototransistors with Multistacked Functional Layers and Composition‐Gradient Heterointerface

“…As shown in Figure a, the nanocrystalline‐CdS (nc‐CdS) film revealed poor field‐effect mobility ( µ FE,CdS = 0.05 cm 2 V −1 s −1 ) and large threshold voltage shift in hysteresis loop (Δ V Th, Hys = 10.0 V) owing to numerous defective sites at the interface/surface of the nc‐CdS film and grain boundaries. In contrast, Sn‐eqi amorphous ZTO semiconductor (Sn‐eqi a‐ZTO) exhibited high‐performance carrier transport behavior ( µ FE, Sn‐eqi a‐ZTO = 2.5 cm 2 V −1 s −1 ) and low charge trap density‐induced narrow hysteresis loop (Δ V Th, Hys = 1.2 V) in the dark state owing to Sn‐induced effective conduction pathway, grain‐boundary‐free amorphous phase, and low Vo concentration . However, the wide optical bandgap (λ ZTO, bandgap = 335 nm) of Sn‐eqi a‐ZTO film causes direct band‐to‐band absorption of UV‐level spectral photons and introduces highly transparent optical properties over most spectral ranges of visible light (Figure b).…”

Application of hydrogen injection and oxidation to low temperature solution-processed oxide semiconductors

“…For this purpose, three peaks were assessed, at 530.4, 531.4 and 532.2 eV. 22 The 530.4 eV was assigned to oxygen bonded to metallic atoms, the 531.4 eV peak to oxygen vacancies and the peak at 532.2 eV to impurity-related oxygen species, such as hydroxyl groups. Table II presents the resulting data.…”