Growth and Characterization of KMgF₃ Single Crystals by the Czochralski Technique under CF₄ Atmosphere

Abstract

KMgF 3 (KMF) single crystals were grown by the Czochralski technique as a new candidate of vacuum-ultra-violet optical materials. The absorption edge of KMF single crystals was 115 nm. The distribution of birefringence in the radial direction was of the order of 10 −7 . The thermal expansion coefficient of KMF single crystals along the 111 orientation was 1.98×10 −5 K −1 . Together with its excellent mechanical properties, these characteristics show KMF to be superior to the current materials.

Induced Absorption Phenomena, Thermoluminescence and Colour Centres in KMgF3, BaLiF3and LiCaAlF6Complex Fluorides

“…In the case of KMF and LiCAF crystal growth, the initial concentrations were 5 mol% KF enriched and 3 mol% LiF and AlF 3 enriched from the stoichiometric one, in order to compensate for the vaporization of KF, LiF and AlF 3 from the melt. 2,20) In the case of BLF crystal growth, the initial concentration was 43 mol% BaF 2 : 57 mol% LiF because BLF melts incongruently. 21) The starting material was placed in a Pt crucible.…”

“…colour centre creation) is possible and reliable. Due to the technology used, extremely low contamination by oxygen ions, OH À and so forth can be guaranteed, [1][2][3]20) so that the observed induced absorption features should not be substantially distorted by the presence of oxygen related defects. F-centre governed induced absorption spectra were obtained in all three complex fluoride systems.…”

“…Their high potential as window materials in the ultra-violet (UV) and vacuum-ultra-violet (VUV) wavelength regions was also identified based on their short wavelength absorption edges. [1][2][3] Recently development for VUV wavelength technologies has increased. In particular, an interest in using 157 nm laser source in projection semiconductor lithography as a successor to 193 nm based systems was announced.…”

Proposed design principle of fluoride-based materials for deep ultraviolet light emitting devices

“…They offer the possibility of being alloyed to form complex materials with wide band gaps and lattice-matched crystal structures, thereby allowing for band-gap engineering and lattice matching as predicted by Nishimatsu et al [9]. As the growth of high-quality bulk fluoride crystals has been successfully demonstrated in LiCaAlF 6 , KMgF 3 , and LiBaF 3 [10][11][12], it is only fitting to explore the possibilities of actual band structure design and appropriately lattice-matched substrate selection using ab initio calculations within the local density approximation (LDA) [9]. In this paper, we suggest three designs of double-heterostructures suitable for light emitting diodes (LEDs) or laser diodes (LDs).…”

Ab Initio Study of the Mechanical, Thermal and Optoelectronic Properties of the Cubic CsBaF3

“…These compounds are generally characterized by their large energy band-gap. Their high potential as window materials in the ultraviolet (UV) and vacuum ultraviolet (VUV) wavelength region was also identied based on their short absorption edges [12,13]. CsBaF 3 is an important member of this ternary family of materials because it could be used as a material for lasers when doped with transition metals.…”