XPS characterisation of neodymium gallate wafers

Surface termination of the NdGaO3(110)

“…This gives the driving force for the diffusion of Ga (O) from deeper layers to the surface and results in a depletion layer of several nm thickness below the surface, as proved by e-AES and RBS results. According to our results Talik et al [15] also observed an escape of Ga not only from the surface, but also from the bulk of NdGaO 3 after thermal treatment at 850-1200 8C temperatures. The investigation of the influence of the main parameters as annealing temperature, time and oxygen partial pressure on the Ga (O) evaporation-diffusion process and on the thickness of the depletion layer is still in progress.…”

“…The crystal structure of NdGaO 3 belongs to the group of rare-earth gallates with orthorhombic GdFeO 3 structure, which can be viewed as a distorted perovskite with a lattice constant of 3.86 Å . Indeed, only few papers have been published describing the surface preparation and the analysis of the surface termination of NdGaO 3 with X-ray photoelectron spectroscopy (XPS) [15], coaxial impact-collision ion scattering spectroscopy (CAICISS) [16], and reflection high energy electron diffraction (RHEED) [17] techniques.…”

Electronic structure of layered titanate Nd2Ti2O7

“…As to Ti-O bonding, the value D Ti = 71.5 eV is intermediate for titanates, the reported values being in the range D Ti = 71.1-72.5 eV [30]. According to structural data [2], the average value of the [45,46], CaNdAlO 4 , D Nd = 452.11 eV [45], NdPO 4 D Nd = 451.6 eV [47]. The magnitude of the D Nd variation is as large as 1.4 eV for this set of Nd-bearing oxides.…”

Characterization of NdGaO3 grown along [110] direction by the XPS method

“…The XPS investigations revealed the changes of the carbon distribution in the crystal ( Table 2). The central sector of the middle part exhibited the smallest carbon content likely for the crystal grown along [0 1 1] direction [2]. The XPS O 1s lines were very sensitive even for small concentration instabilities, showing a complicated structure ( Fig.…”

“…NdGaO 3 exhibits much better lattice matching to GaN than sapphire (0 0 0 1), while the thermal expansion coefficients of NdGaO 3 are similar to that of sapphire [1]. Recently, the XPS investigations of the substrates, which were the (0 1 1) gallium planes, obtained from the cone, middle part and the end of the NdGaO 3 crystal grown along the [0 1 1] direction, were performed [2]. They revealed the change of the chemical composition of the wafers cut from the beginning, middle and end part of the crystal grown along this direction and the existence of the core level satellites at low binding energy related to defects.…”