Effects of nitrogen incorporation on the interface chemical bonding states, optical dielectric function, band alignment, and electrical properties of sputtering-derived HfTiO high-k gate dielectrics on GaAs substrates have been studied by angle resolved X-ray photoemission spectroscopy (ARXPS), spectroscopy ellipsometry (SE), and electrical measurements. XPS analysis has confirmed that the interfacial layer of a HfTiO/GaAs gate stack is suppressed effectively after nitrogen incorporation. Analysis by SE has confirmed that reduction in band gap and increase in refractive index are observed with the incorporation of nitrogen. Reduction in valence band offset and increase in conduction band offset have been observed for a HfTiON/GaAs gate stack. Electrical measurements based on metal-oxide-semiconductor (MOS) capacitors have shown that the MOS capacitor with a HfTiON/GaAs stacked gate dielectric annealed at 600 °C exhibits low interface-state density (2.8 × 10¹² cm⁻² eV⁻¹), small gate leakage current (2.67 × 10⁻⁵ A cm⁻² at V_g = V_fb + V), and large dielectric constant (25.8). The involved mechanisms may originate from the decrease in the interface state density and the increase in the conduction band offset. The appropriate band offset relative to GaAs and excellent interface properties render HfTiON/GaAs as promising gate stacks in future III–V-based devices.

Solution based deposition has been recently considered as a viable option for low-cost flexible electronics. In this context, research efforts have been increasingly focused on the development of suitable solution-processed materials for oxide based transistors. In this work, we report a fully solution synthesis route, using 2-methoxyethanol as solvent, for the preparation of In₂O₃ thin films and ZrO_x gate dielectrics, as well as the fabrication of In₂O₃-based TFTs. To verify the possible applications of ZrO_x thin films as the gate dielectric in complementary metal oxide semiconductor (CMOS) electronics, fully solution-induced In₂O₃ TFTs based on ZrO₂ dielectrics have been integrated and investigated. The devices, with an optimized annealing temperature of 300 °C, have demonstrated high electrical performance and operational stability at a low voltage of 2 V, including a high μ_sat of 4.42 cm² V⁻¹ s⁻¹, low threshold voltage of 0.31 V, threshold voltage shift of 0.15 V under positive bias stress for 7200 s, and large I_on/I_off of 7.5 × 10⁷, respectively. The as-fabricated In₂O₃/ZrO_x TFTs enable fully solution-derived oxide TFTs for potential application in portable and low-power consumption electronics.

The trapping structure and plasmons have become two major ways to enhance light absorption and carrier transport to achieve high-performance full-spectrum solar cells.