Optimization of electrical performance and stability of fully solution-driven α-InGaZnO thin-film transistors by graphene quantum dots

This work presents solution-processed high-performance graphene quantum dots (GQDs) decorated amorphous InGaZnO (α-IGZO) thin-film transistors (TFTs) based on ZrOx as gate dielectrics. Compare with pure IGZO TFTs, GQDs-modified α-IGZO TFTs devices with optimized doping content have demonstrated better performances, including a larger field-effect mobility (μFE) of 35.91 cm2 V–1 s–1, a higher on/off current ratio (ION/IOFF) of 5.04 × 108, a smaller subthreshold swing (SS) of 0.11 V dec–1 and a smaller interfacial trap states (Dit, 1.57 × 1012 cm−2). Moreover, the GQDs-doped IGZO TFTs with a doping concentration of 0.5 mg ml–1 have shown excellent stability under bias stress and illumination stress conditions. To demonstrate the potential applications of α-IGZO TFTs in logic circuits, a resistor-loaded unipolar inverter based on GQDs-IGZO/ZrOx has been integrated, demonstrating good dynamic behavior and a high gain of 9.3. Low-frequency noise (LFN) characteristics of GQDs-IGZO/ZrOx TFTs have suggested that the fluctuations in mobility are the noise source. Based on all the experimental findings, it can be concluded that solution-processed GQDs-IGZO/ZrOx TFT may envision promising applications in optoelectronics.