Density: 2.10 g/cm3. Film deposited at room temperature.
M. Fernández-Perea, J. I. Larruquert, J. A. Aznárez, J. A. Méndez, M. Vidal-Dasilva, E. Gullikson, A. Aquila, R. Soufli, and J. L. G. Fierro. Optical constants of electron-beam evaporated boron films in the 6.8-900eV photon energy range, J. Opt. Soc. Am. A24, 3800-3807 (2007) (Numerical data kindly provided by Juan Larruquert)
Boron (B) is a chemical element with the atomic number 5 and is classified as a metalloid. In its crystalline form, it exhibits a complex structure with icosahedral units and is a poor conductor of electricity. Boron is not typically used as a standalone material in optical applications, but it plays a vital role as a dopant in semiconductors and optical fibers. In fiber optics, boron-doped fibers are used to shift the zero-dispersion wavelength and control nonlinear effects. In semiconductor applications, boron is often used to create p-type materials, serving as an acceptor impurity in materials like silicon. It also finds use in borosilicate glasses, which are prized for their low thermal expansion coefficients and high resistance to thermal shock, making them useful for applications requiring stability under fluctuating temperatures. In addition, boron nitride (BN) is known for its high thermal conductivity and electrical resistivity, making it useful in electronic packaging and thermal management systems. Despite its relative scarcity in pure optical applications, boron remains an important element in the broader landscape of materials science, contributing to the functionality of a variety of optoelectronic devices and systems.