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All-inorganic CsPbX 3 (X = Cl, Br, and I) nanocrystals (NCs) are emerging as attractive semiconductor materials because of their outstanding optical properties. The low resistance of CsPbX 3 NCs to light, heat, oxygen, and water has been recognized as a major obstacle to their practical applications. Here, we demonstrate that the stability of CsPbX 3 NC films can be dramatically enhanced by Ar plasma treatment. It is revealed that plasma irradiation can induce ligand polymerization in the NC films if the ligands contain unsaturated carbon bonds. The ligand polymerization leads to encapsulation of the NCs in the ligand polymers. Because of the precise localization of the in situ ligand polymerization under plasma irradiation and the high NC content in the films without extra additives, the polymerized area can be precisely defined down to several micrometers. This enables easy fabrication of high-resolution NC pixels for next generation displays.

In this study, we report on the growth of crystalline InN thin films by plasma-enhanced atomic layer deposition (PE-ALD). By systematically investigating the growth parameters, we determined the process window for crystalline InN films growth by PE-ALD. Under the optimal conditions, we compared Si (100), Al2O3 (0001), and ZnO (0001) substrates with different lattice mismatches to InN. High resolution X-ray diffraction (HR-XRD) measurements showed that we obtained the epitaxial InN thin film on the ZnO (0001) substrate, which has the smallest lattice mismatch. The crystal orientation relationship is found to be InN[0001]∥ZnO[0001] and InN[10−10]∥ZnO[10−10]. HR-XRD and high resolution transmission electron microscopy measurements revealed that the InN films are fully relaxed, and no voids or interlayer is observed at the interface. Our results show that the epitaxial growth of the InN film can be obtained by PE-ALD at low temperature.

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The resistive switching (RS) mechanism of hybrid organic-inorganic perovskites has not been clearly understood until now. A switchable diode-like RS behavior in MAPbBr3 single crystals using Au (or Pt) symmetric electrodes is reported. Both the high resistance state (HRS) and low resistance state (LRS) are electrode-area dependent and light responsive. We propose an electric-field-driven inner p-n junction accompanied by a trap-controlled space-charge-limited conduction (SCLC) conduction mechanism to explain this switchable diode-like RS behavior in MAPbBr3 single crystals.

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A GaN/CH3NH3PbBr3 heterojunction was fabricated by depositing a GaN thin layer on a CH3NH3PbBr3 single crystal by plasma enhanced atomic layer deposition. The band alignment of the GaN/CH3NH3PbBr3 heterojunction was studied by x-ray photoelectron spectroscopy. The valance band offset (VBO) is directly determined to be 0.13 ± 0.08 eV. The conduction band offset is deduced from the VBO and the band gaps, which turned out to be 1.39 ± 0.12 eV. Thus, the band alignment of the GaN/CH3NH3PbBr3 heterojunction is determined to be type-I. These results show that GaN is a promising material for carrier confinement in halide perovskite based light emitting devices.

Due to indispensable ligands, polluted organic solution, or complex vapour deposition, stable CsPbBr3 film is hard to be prepared directly using a simple and environmentally friendly method. To improve the stability of CsPbBr3 film and its synthesis methods, the double‐films solid phase reaction was developed, and Cs4PbBr6/CsPbBr3 composites were designed. Although the synthesized particle had a size of 2–5 μm, much larger than that of quantum dots, in ambient conditions the composites films still showed good photoluminescence properties, with the highest photoluminescence quantum yield of 80%. It had good stability against air, temperature and humidity, and even had interesting fluorescence‐enhanced phenomenon after about 4 days.