The role of substrates in thin film growth encompasses structural and morphological characteristics which, as a consequence, can also affect electronic properties. This article reports studies on the structural, morphological, and magnetotransport properties of Cadmium Oxide (CdO) films grown on two distinct substrates, amorphous glass, and crystalline silicon, by spray pyrolysis technique. The crystallinity of CdO grown on Silicon (CdO/Si) is higher as compared to the CdO grown on glass (CdO/glass), although CdO/Si morphology presents a dome-like surface. In both cases, samples showed exponential behavior in the electrical resistance curves in the temperature ranges between 1.9 K to 300 K and negative magnetoresistance, due to the weak localization effect, for temperatures lower than 110 K. The highest electronic mobility for CdO/Si is attributed to the better crystallinity of the domes. The weak localization effect is correlated by the 3D Kawabata model, fitting the magnetoresistance curves to determine the phase coherence length over a temperature range of 4.2 K to 100 K. Despite the huge differences in the morphological and electrical properties, the linear behavior of temperature-dependent phase coherence length, attributed to the electron-electron interaction in this temperature range, is found to be independent of the employed substrate. This remarkable result indicates the potential application of the low-cost spray pyrolysis technique for producing high-speed photodetectors.

We present a systematic investigation of the morphological and magnetotransport properties of Zn1−xCdxO/CdO heterostructures managing the electronic barrier by changing x values between 0.50 and 0.95. From physical parameters such as roughness and crystallite size obtained through scanning electron microscopy and x-ray diffraction, we established a correlation between the disorder degree and the amplitude of the negative magnetoresistance as well as the nature of the dominating inelastic scattering mechanisms. The magnetoresistance measurements revealed a negative amplitude for all heterostructures, which clearly shows that the weak localization effect is observed in the low temperature range. Applying the three-dimensional weak localization theory (Kawabata 3D), we extract the phase coherence length, and a relatively large value (maximum reaches 135 nm at 4.2 K) is obtained for the Zn0.05Cd0.95O/CdO heterostructure.

In this work, we performed magnetotransport measurements in an n-type single quantum well (QW) grown by molecular beam epitaxy and found that, under illumination, the QW presents metallic behavior and Shubnikov-de Haas oscillations at low temperatures. Under dark conditions, the QW is an insulator and no quantum oscillations are observed. Several peaks were identified in the fast Fourier transform curves and some were addressed to the longitudinal and oblique valleys that compound the multiple-valley Fermi surface of PbTe. By investigating the Berry phases of the oscillation, a phase of ∼0.5, characteristic of Dirac Fermions, was obtained, in accordance with recent theoretical predictions of transport via topological surface states in PbTe films.

We report on the observation of the Shubnikov–de Haas oscillation in a polycrystalline ZnO/CdO heterostructure grown on a silicon substrate by a spray pyrolysis technique in temperatures below 6 K. From the analysis of these quantum oscillations, we obtained the cyclotronic effective mass, the 2D carrier concentration, and the thickness of the two-dimensional electron gas in the interface of the two layers. The results suggest that a two-dimensional electron gas is successfully obtained at the ZnO/CdO interface.

This work presents the results of magnetotransport measurements performed on a 156 nm-thick Bi2Te3 epitaxial film in the temperature range of 1.9–300 K, showing Shubnikov–de Haas oscillations for temperatures below 50 K. A detailed analysis of oscillations as a function of temperature provides the main transport parameters, including the Landé g-factor and cyclotronic masses. A systematic analysis of fast Fourier transform, performed on the oscillations, indicates that the origin of the oscillation pattern is not related to the topological surface states but from the Rashba splitting of the Bi2Te3 Fermi surface.