We report the development of a scanning confocal microscope dedicated to photoluminescence in the 200 nm-wavelength range for samples at cryogenic temperatures (5 K–300 K). We demonstrate the performances of our deep ultraviolet cryomicroscope in high-quality hexagonal boron nitride (hBN) crystals, although it can be utilized for biological studies in its range of operating wavelengths. From the mapping of photoluminescence, we bring evidence for the suppression of extrinsic recombination channels in regions free from defects. The observation of emission spectra dominated by intrinsic recombination processes was never reported before in hBN by means of photoluminescence spectroscopy. We show that photoluminescence tomography now competes with cathodoluminescence and that deep ultraviolet cryomicroscopy by photoluminescence is a novel powerful tool in materials science applications, with the great advantage of an efficient non-invasive photo-excitation of carriers.

中文翻译：

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氮化硼中的深紫外高光谱低温显微术：缺陷密度超低的晶体中的光致发光

我们报道了在低温（5 K–300 K）下用于样品在200 nm波长范围内光致发光的扫描共聚焦显微镜的发展。尽管可以在工作波长范围内用于生物学研究，但我们证明了深紫外冷冻显微镜在高质量的六方氮化硼（hBN）晶体中的性能。从光致发光的映射，我们为无缺陷区域中的外在重组通道的抑制提供了证据。在hBN中，以前从未通过光致发光光谱法观察到由内在重组过程主导的发射光谱。