Using low-resistance indium contacts, we measured some transport properties of undoped vapor-liquid-solid grown tin oxide monocrystals with a belt shape. From the transport measurements, the two following conduction mechanisms were investigated: thermal activation and variable range hopping. An energy gap of 3.8 eV was found. The energy gap was confirmed by thermally activated measurements in the range between 10 and 300 K. For high temperatures (T>300 K), the influence of the disorder caused by the superficial ions layer is measurable. The electron transport in this case was found to be governed by the well known variable range hopping mechanism and the spatial extension of carrier’s wavelength was calculated to be 4 nm.

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At 4th-generation synchrotron nanoprobes with optimized photon density, focusing optics systems often require mirrors arrangements with high demagnification factors to achieve diffraction-limited beam sizes (∠ 100 nm) and still high photon flux. All the components’ contributions to the surface error must be at the same level (a few nanometers) and angular stability (lower than 10 nrad RMS) becomes a bottleneck issue. Therefore, the design of ultra-stable mirror mechanics has to follow a systems perspective, where precision engineering, metrology and alignment strategies are considered simultaneously. For the latest design at Sirius/LNLS, an exactly-constrained KB set with minimum number of adjustment degrees for increased stiffness and stability was also bounded by an alignment error budget in the order of tens of microns by construction, pushing metrology limits during alignment and validation phases. This work presents a two-phase strategy for metrology-assisted assembly and figure validation of elliptical mirror sets, starting at a Fizeau Interferometer system (FZI) and finishing at a Coordinate Measuring Machine (CMM). The first phase validates surface quality by scanning mirror position and automatically realigning interferometry fringe patterns, while pixel-level stitching techniques are employed to characterize the surface error over the mirror’s length. The stitching algorithm includes self-calibration of lens errors and uses multiple CPU cores for expedite processing. The second phase consists of fiducializing the elliptical figures of each mirror into their own substrates and assembling both mirrors with regard to each other by using a least-squares fit of the center and rotation angle of each fixed ellipse, obtained from the manufacturer’s documentation, and confirmed at the first phase. This workflow was applied and demonstrated at an ultra-stable exactly-constrained KB system, reaching sufficient alignment accuracy.