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ZnSnN2 has potential applications in photocatalysis and photovoltaics. However, the difficulty in preparing nondegenerate ZnSnN2 hinders its device application. Here, the preparation of low-electron-density nanocrystalline ZnSnN2 and its device application are demonstrated. Nanocrystalline ZnSnN2 was prepared with reactive sputtering. Nanocrystalline ZnSnN2 with an electron density of approximately 1017 cm−3 can be obtained after annealing at 300 °C. Nanocrystalline ZnSnN2 is found to form Schottky contact with Ag. Both the current I vs. voltage V curves and the capacitance C vs. voltage V curves of these samples follow the related theories of crystalline semiconductors due to the limited long-range order provided by the crystallites with sizes of 2–10 nm. The I−V curves together with the nonlinear C−2−V curves imply that there are interface states at the Ag-nanocrystalline ZnSnN2 interface. The application of nanocrystalline ZnSnN2 to heterojunction solar cells is also demonstrated. [ABSTRACT FROM AUTHOR]

To meet device applications, it is essential to fabricate nondegenerate ZnSnN2 with higher mobility. Herein, the chemical potential of nitrogen was improved under Zn-rich sputtering conditions and nondegenerate ZnSnN2 with mobility higher than 20 cm2 V−1 s−1 was successfully fabricated. The properties of the samples were characterized. The obtained ZnSnN2 is wurstite. Band conduction is observed in the range 300–100 K and nearest neighbour hopping is observed in the range 100–70 K. The forbidden band gap is about 1.43 eV and Sn substituting Zn is the major donor, whose ionization energy is 34.6 meV. Improving the chemical potential of nitrogen under Zn-rich conditions effectively changes the off-stoichiometry of ZnSnN2 and unintentionally increases oxygen doping, which finally leads to a decrease in electron density and an increase in mobility. [ABSTRACT FROM AUTHOR]

Zn1− xSn xO thin films were deposited on K9 glass and Si substrates by co-sputtering Zn and Sn targets under atmospheres of Ar and O2. The samples were then characterized with X-ray diffraction (XRD), Raman, energy-dispersive X-ray spectroscopy (EDX), Seebeck effect, four-probe instrument, and UV/VIS spectrophotometry. XRD and Raman show that all the samples are hexagonal and Sn doping increases the stress greatly. EDX demonstrates that the atomic ratio of Sn to Sn plus Zn is 0.04-0.07. All the samples are n-type. The resistivity of Zn1− xSn xO is much smaller than that of undoped ZnO deposited under the same conditions. The optical bandgap of Zn1− xSn xO is also reduced compared with that of ZnO deposited under the same conditions. [ABSTRACT FROM AUTHOR]

Cu(In, Ga)Se (CIGS) thin films were fabricated by ion beam sputtering deposition from a single quaternary target at different substrate temperatures ( T). The thin films were characterized with X-ray diffractometry, scanning electron microscopy, energy-dispersive X-ray spectroscopy and four-point probe technique to study the microstructures, surface morphology, composition and electrical properties, respectively. The results show that the films grown above 400 °C are of chalcopyrite structure. Cu(InGa)Se thin film was obtained when T is 550 °C. The Cu and Se atomic percentage when T is above 500 °C is higher than when T is below 500 °C. With the increase in T, the surfaces morphology of the films is denser and the resistivity of the films decreases. [ABSTRACT FROM AUTHOR]

To evaluate the influence of film thickness on the structural, electrical, and optical properties of Al-doped ZnO (AZO) films, a set of polycrystalline AZO samples with different thickness were deposited on glass substrates by ion-beam sputtering deposition (IBSD). X-ray diffraction (XRD), atomic force microscopy (AFM), energy-dispersive x-ray spectroscopy (EDS), four-point probe measurements, and spectrophotometry were used to characterize the films. XRD showed that all the AZO films had preferred c-axis orientation. The ZnO (110) peak appeared, and the intensity increased, with increasing thickness. All the samples exhibited compressive intrinsic stresses. AFM showed that the grain size along with the root-mean-square (RMS) roughness increased with increasing thickness. The decrease of resistivity is due to the corresponding change in grain size, surface morphology, and chemical composition. The average optical transmittance of the AZO films was over 80%, and a sharp fundamental absorption edge with red-shifting was observed in the visible region. The optical band gap decreased from 3.95 eV to 3.80 eV when the AZO film thickness increased from 100 nm to 500 nm. [ABSTRACT FROM AUTHOR]

In conventional thin film thermoelectric generators, heat flow running vertical to film surface is used. The hot side and the cold side are just separated by the thickness of the films and to maintain the temperature difference between both sides remains a key challenge. Here, we demonstrate the properties of our designed thin film thermoelectric generators with heat flow running parallel to film surface, where a larger temperature difference between both sides is maintained. The maximum output power of our generator can reach 19.13 μW at the temperature difference of 85 K. [ABSTRACT FROM AUTHOR]