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Ultra-wide bandgap semiconductors with exceptional advantages have potential use in ultrahigh power, ultrahigh frequency devices, and other applications. In this paper, a series of high-quality Nb-doped ZrxSn1−xO2 (Nb:ZrxSn1−xO2) alloy epitaxial films were prepared on c-plane sapphire substrates by pulsed laser deposition. A greater proportion of Zr successfully widened the optical bandgap of SnO2 up to 4.70 from 4.28 eV. Interestingly, although Nb is a common n-type dopant for SnO2, the conductivity of Nb:ZrxSn1−xO2 decreased with increasing Zr content. The greater activation energy Ea of the films with more Zr contents was determined by variable resistance measurements and rationalized by the first-principles calculations. The higher Zr content leads to a lower conductivity in the films. This is because the electronegativity of Zr is smaller than that of Sn and Nb, making it easier for O to attract electrons from Zr and Nb donating less electrons with increasing Zr content. It leads to more electrons filling the Nb 4d orbital and brings the donor level further down from the conduction band minimum. However, Nb:ZrxSn1−xO2 with a low Zr content of x = 0.1 has good electrical conductivity, with a carrier density of 5.426 × 1020 cm−3 and a resistivity of 7.89 × 10−3 Ω cm, and simultaneously a broadened bandgap of 4.4 eV. Therefore, Nb can act as an effective n-type dopant for ZrxSn1−xO2 with proper Zr content, making Nb-doped ZrxSn1−xO2 promising for developing ultraviolet-transparent conductive electrodes. [ABSTRACT FROM AUTHOR]

Hybrid bismuth halides perovskites have emerged as promising candidates for X‐ray detection, due to the strong absorptivity of high‐energy X‐ray photons, high resistivity, large carrier diffusion length and low toxicity. However, the mostly investigated hybrid bismuth iodides single crystals are usually opaque and require a harsh synthesis process. Herein, novel one‐dimensional (1D) pentamethylenediamine bismuth bromide (PDA)BiBr5 single crystals were synthesized via an antisolvent‐assisted crystallization method at room temperature. Bulk (PDA)BiBr5 single crystals have sizes of 10×1.3×1.5 mm3 and high transparency. They are shown to have low density of defects of 2.0×1010 cm−3 and obvious photoconductivity. Moreover, they exhibit large bulk resistivity of 2.13×1011 Ω cm and good X‐ray attenuation coefficient. Consequently, the vertical structured (PDA)BiBr5 single crystal X‐ray photoconductor produces a sensitivity of 3.8 μC Gyair−1 cm−2. This study provides a facile strategy for synthesizing bulk hybrid bismuth bromides single crystals with potential X‐ray detection application. [ABSTRACT FROM AUTHOR]

Hybrid bismuth halides perovskites have emerged as promising candidates for X-ray detection, due to the strong absorptivity of high-energy X-ray photons, high resistivity, large carrier diffusion length and low toxicity. However, the mostly investigated hybrid bismuth iodides single crystals are usually opaque and require a harsh synthesis process. Herein, novel one-dimensional (1D) pentamethylenediamine bismuth bromide (PDA)BiBr 5 single crystals were synthesized via an antisolvent-assisted crystallization method at room temperature. Bulk (PDA)BiBr 5 single crystals have sizes of 10×1.3×1.5 mm 3 and high transparency. They are shown to have low density of defects of 2.0×10 10  cm -3 and obvious photoconductivity. Moreover, they exhibit large bulk resistivity of 2.13×10 11  Ω cm and good X-ray attenuation coefficient. Consequently, the vertical structured (PDA)BiBr 5 single crystal X-ray photoconductor produces a sensitivity of 3.8 μC Gy air -1  cm -2 . This study provides a facile strategy for synthesizing bulk hybrid bismuth bromides single crystals with potential X-ray detection application., (© 2021 Wiley-VCH GmbH.)