A yellow-orange nitrogen-doped zinc oxide (ZnO:N) film was deposited on a quartz glass substrate at $510\mathrm{K}$ by reactive radio-frequency magnetron sputtering of a ZnO target with sputtering gas of nitrogen. The lattice constants of the as-grown ZnO:N are much larger than those of undoped ZnO, and decrease with increasing annealing temperature due to escape of the nitrogen from the ZnO:N and decrease of tensile stress, accompanied with color change from yellow-orange to pale yellow. The nitrogen occupies two chemical environments in the ZnO:N based on x-ray photoelectron spectroscopy measurement. One is ${\mathrm{N}}_{\mathrm{O}}$ acceptor formed by substitution of N atom for O sublattice, and another is ${\left({\mathrm{N}}_2\right)}_{\mathrm{O}}$ double donors produced by substitution of N molecular for O site, which make the lattice constants expanded. The as-grown ZnO:N film shows insulating, but behaves $p$ -type conduction in the dark after annealed at $863\mathrm{K}$ for $1\mathrm{h}$ under ${10}^{-3}\mathrm{Pa}$ . Unfortunately, the $p$ -type conduction is not stable and reverts to $n$ type soon. However, after illuminated by sunlight for several minutes, the $n$ -type ZnO:N transforms into $p$ type again. The mechanism of the transformation of the conductivity behavior is discussed in the present work.

We report a novel Au-assist exfoliation and non-destructive transfer method to fabricate the large-scale Bi ₂ Se ₃ thin nanosheet. Furthermore, a broken-gap tunneling phototransistor is designed by combing 2H-MoTe ₂ and Bi ₂ Se ₃ .

Single wurtzite p-type Zn 1 − y Cu y O 1 − x S x alloy films with 0.081 ≤ x ≤ 0.186 and 0.09 ≤ y ≤ 0.159 were grown on quartz reproducibly by magnetron sputtering. The alloys show very stable p-type conductivity with a hole concentration of 4.31 – 5.78 × 10 19 cm − 3 , a resistivity of 0.29 – 0.34 Ω cm and a mobility of 0.32 – 0.49 cm 2 V − 1 s − 1 . The p-type conductivity is attributed to substitution of Cu + 1 for the Zn site, and the ionization energy of the Cu + 1 acceptor is measured to be 53 meV, much less than that of Cu-doped ZnO reported previously. The small ionization energy is due to Cu heavy doping and increase in valence band maximum of ZnO induced by alloying with S.

Two-dimensional (2D) bismuth oxyselenide (Bi₂O₂Se) has attracted increasing attention due to its high mobility, tunable band gap, and air stability. The surface reconstruction of cleaved Bi₂O₂Se due to the electrostatic interlayer interactions can lead to the in-plane anisotropic structure and physics. In this work, we first discovered the strong anisotropy in phonon modes through the angle-resolved polarized Raman (ARPR) spectra. Benefiting from the anisotropic feature, a high-performance polarization-sensitive photodetector has been achieved by constructing a heterostructure composed of the multilayer Bi₂O₂Se as polarized-light sensitizers and 2D WSe₂ as a photocarrier transport channel. The detectors exhibit broadband response spectra from 405 to 1064 nm along with high responsivity, fast speed, and high sensitivity owing to the photogating effect in this device architecture. More importantly, the photocurrent shows strong light polarization dependence with the maximum dichroism ratio of 4.9, and a reversal is observed for the angle-dependent photocurrent excited by polarized 405 and 635 nm light. This work provides new insight in terms of optical and photocurrent anisotropy of exfoliated Bi₂O₂Se and expands its applications in angle-resolved electronics and optoelectronics.