Growth, optical and microstructural properties of PbB4O7 plate crystals

Abstract Centimeter-sized optical quality plate-like PbB 4 O 7 crystals have been grown by Czochralski method. The fundamental absorption edge has been found at 237 nm (corresponding bandgap 5.75 eV) with the distinct sideband protruding up to 300 nm. The crystals are well faceted with the (1 0 0), (0 1 0) and (1 0 1) planes, (1 0 0) surfaces being mostly developed. The etching in diluted nitric acid (5 wt.%) at the temperature of 90 °C have been used to reveal the defect structure and remove melt residuals. The (1 0 0) surface shows the presence of etching pits and twin boundaries. The Kikuchi line pattern and developed microrelief with the roughness of ∼8 nm have been observed by RHEED and AFM, respectively.