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Metal oxide semiconductors have several advantages over conventional Si-based materials, including high mobility even in the amorphous state, excellent optical transparency, and compatibility with low-cost fabrication processes. Despite the toxic nature of cadmium compounds, the excellent electrical and optical properties of CdO have attracted research attention for potential applications in high-performance military and aerospace technologies. In this study, an amorphous cadmium gallium oxide (a-CdGaO)-based thin-film transistor (TFT) (optimized at Cd : Ga ratio of 5.5 : 4.5) is demonstrated, with a maximum mobility of 17.68 (14.10 in average) cm2 V−1 s−1, an on/off current ratio (Ion/Ioff) of 1.01 × 109, a threshold voltage (Vth) of 0.73 V, optical transmittance (T550) > 90%, a bias stability of 4.36 V under positive bias stress (PBS), a bias stability of −1.83 V under negative bias stress (NBS), and a high frequency of 250 kHz when applied on a seven-stage oscillator ring circuit. Additionally, the optimized a-Cd5.5Ga4.5O12.25 device showed excellent stability over time with negligible change of mobility and Vth values after one week exposure to ambient air condition. [ABSTRACT FROM AUTHOR]

Metal halide perovskites have attracted a considerable amount of research attention with significant progress made in the field of optoelectronics. Despite their outstanding electrical characteristics, structural defects impede their potential performance due to the polycrystalline nature of solution‐processed perovskite films. Herein, the effective p‐type doping and defect passivation of phenethylammonium tin iodide ((PEA)2SnI4) perovskite films using xanthate additives as a sulfur source is reported. Sulfur can be introduced to the iodine vacancies mainly at the grain boundaries of the perovskite film, passivating the electrical defects originating from the iodine vacancy and increasing the hole concentration. The Fermi‐level shift toward the valence band maximum of the sulfur‐doped perovskite film is confirmed using ultraviolet photoemission spectroscopy, resulting in p‐type doping. Finally, the electrical performance improvement for the 0.2% sulfur‐doped (PEA)2SnI4 thin‐film transistor with a mobility of 1.45 cm2 V−1 s−1, an on/off ratio of 2.9 × 105 is demonstrated, and hysteresis of 10 V is reduced. [ABSTRACT FROM AUTHOR]

Transparent oxide semiconductors are successfully implemented as thin‐film transistors (TFTs) for large‐area display applications with superior electrical performance in comparison with that of conventional amorphous silicon. However, further development of high‐performance oxide semiconductors is hindered by the trade‐off between mobility and stability. Mixed metal composition containing heavy metal cations shows high‐mobility/low‐stability and light metal cations exhibits low‐mobility/high‐stability. A novel material design strategy for realizing a high‐performance oxide semiconductor for TFTs through partial substitution of Se or S for O in In2O3 is reported. In contrast to the conventional small‐sized Ga substitution for suppressing oxygen vacancies, the replacement of O by Se or S results in lattice stabilization and oxygen‐vacancy suppression, consequently stabilizing Se‐ or S‐incorporated In2O3 TFTs. In2O3:Se TFTs exhibit an average field‐effect mobility of 6.1 cm2 V−1s−1, ON/OFF current ratio (Ion/Ioff) of 108, and excellent operational stability with threshold voltage shift values of <0.10 V at a positive and negative bias stress for 10 000 s. Furthermore, the seven‐stage ring oscillator circuit operating at a supply bias of 20 V exhibits an oscillation frequency of >805 kHz and a corresponding propagation delay of <90 ns per stage. [ABSTRACT FROM AUTHOR]

A synthesis of EuO was carried out through the thermal reduction of Eu2O3 by a stoichiometric quantity of metallic Eu. EuO undergoes a second-order phase transformation at ~69 k from the ferromagnetic to the paramagnetic state on heating as indicated by the heat capacity and magnetic measurements.

Copper iodide (CuI) has gained attention as a highly conductive p-type transparent material. Here, we investigate the phase stability of I-rich cubic CuI phases with Cu-vacancy defects by performing hybrid-density functional theory calculations. In the Cu-rich equilibrium condition, the nearly stoichiometric phase is the ground state with quenched Cu-vacancy defects, and the Cu-vacancy defect is a major acceptor responsible for the intrinsic p-type conductivity. In contrast, in the I-rich condition, the off-stoichiometric Cu1−xIx phase (x = 0.5–0.55) containing high-density Cu vacancies is stabilized with configuration entropy from Cu vacancies. As the off-stoichiometric phases contain high-density neutral Cu vacancies, the hole transport can be hindered, and the hole mobility could be reduced. [ABSTRACT FROM AUTHOR]