A high quality inclusion-free Bi2Se3 crystal has been grown by the Bridgman method with the use of a rotating heat field. A large-area atomically flat Bi2Se3(0001) surface of excellent crystallographic quality has been formed by cleavage. Chemical and microstructural properties of the surface have been evaluated with reflection high-energy electron diffraction, atomic force microscopy (AFM), scanning tunneling microscopy (STM), spectroscopic ellipsometry, and X-ray photoelectron spectroscopy. There was no Bi2Se3(0001) surface oxidation detected after over a month in air under ambient conditions as shown by comparative core level spectroscopy, AFM, and STM.

A high-quality inclusion-free ZnWO 4 crystal 90 mm in diameter and with a mass of up to 8 kg was grown by the low thermal gradient Czochralski technique. Crystallographic properties of ZnWO 4 (010) cleaved surfaces were evaluated with reflection high energy electron diffraction (RHEED), and the electronic structure of the surface was studied using X-ray photoelectron spectroscopy (XPS). A system of Kikuchi lines was observed for cleaved ZnWO 4 (010) by RHEED confirming the high crystallographic state of the surface. The XPS valenceband and core-level spectra of ZnWO 4 (010) have been measured. The XPS measurements reveal that tungsten and zinc atoms are in the formal valences þ6 and þ2, respectively, on cleaved ZnWO 4 (010) surface. The 3.0 keV Ar þ bombardment of the surface causes partial transformation of tungsten ions from W 6þ to lower valence states; however, no partial loss of oxygen atoms belonging to ZnO 6 octahedra occurs due to this bombardment of the ZnWO 4 (010) surface because after this treatment zinc remains exclusively in the formal valence þ2. The WÀO chemical bonding is considered in tungstates including ZnWO 4 .

Inertness of the cleaved (0001) surface of the Bi2Se3 single crystal, grown by modified Bridgman method, to oxidation has been demonstrated by X-ray photoelectron spectroscopy, scanning tunneling microscopy, and by ab initio DFT calculations. No intrinsic bismuth and selenium oxides are formed on the low-defect, atomically flat Bi2Se3(0001)-(1×1) surface after a long-time air exposure. The inertness of Bi2Se3(0001) to O2 and NO2, as well as bismuth-oxygen bonding formation under molecular adsorption in the Se vacancy was supported by DFT calculations.