Complex Fourier transformation (CFT) has been employed to analyse contactless electroreflectance (CER) spectra from an undoped-n + GaAs structure with various ac modulations and dc bias voltages. The CFT spectra of CER have been compared with those of photoreflectance (PR). It has been found that the CER non-flat modulation is between the built-in electric field and a larger electric field which increases with the modulation voltage. The result has been explained by the screening of the applied modulation electric field in one of the two half modulation cycles and the trapping of electrons in surface states in the other half modulation cycle. The dc bias does not change the CER spectra, hence their CFT spectra. This is because of the screening of the applied dc bias electric field.

Contactless electroreflectance (CER) and photoreflectance (PR) measurements have been performed on samples with the structure of an n-doped GaAs epitaxial layer on a semi-insulating GaAs substrate. Modulated reflectance signals from the n-GaAs surface and those from the n-GaAs/SI-GaAs interface are superposed in PR spectra. For the case of CER measurement, however, Franz-Keldysh oscillations (FKOs) from the interface, which are observed in PR spectra, cannot be detected. This discrepancy is attributed to different modulation mechanisms of CER and PR. In CER experiments, the electric field modulation cannot be added to the interfacial electric field because of the effective screening by the fast response of carriers across the interface. FKOs from the interface without any perturbation by the surface signals are extracted by subtracting CER spectra from PR spectra.

The preparation and properties of Tl-2212 (Tl2Ba2CaCu2O8) thin films on biaxially textured Ni substrates, buffered with CeO2/YSZ/CeO2 trilayers, have been studied. Tl-2212 thin films were grown using a two-step fabrication process that involved magnetron sputtering and low temperature post-annealing. XRD θ–2θ scans, rocking curves and φ-scans proved that the Tl-2212 thin films were epitaxially grown on the buffered RABiTS. The critical temperature Tc and critical current Jc (77 K, 0 T) were 103 K and 2.6 MA cm−2, respectively.