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Electrical Resistivity and Microwave Transmission of Hexagonal Boron Nitride
Author(s) -
FREDERIKSE H. P. R.,
KAHN A. H.,
DRAGOO A. L.,
HOSLER W. R.
Publication year - 1985
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1985.tb09650.x
Subject(s) - electrical resistivity and conductivity , materials science , boron nitride , microwave , boron , nitride , conductivity , absorption (acoustics) , band gap , semiconductor , composite material , mineralogy , layer (electronics) , optoelectronics , chemistry , physics , organic chemistry , quantum mechanics , electrical engineering , engineering
The dc conductivity of hexagonal boron nitride (BN) and BN‐containing composites was measured as a function of temperature up to 2400°C. The results confirm that at high temperatures BN is an intrinsic semiconductor with an energy gap of 0.99 ± 0.06 aJ (6.2 ± 0.4 eV) at T = 0 K. Extrapolated values for the resistivity of BN in the range 2600° to 3000°C are used to analyze the absorption, reflectivity, and transmissivity of a BN window when subjected to microwave radiation under atmospheric reentry conditions. It appears that the transmissivity is of the order of 1 to 10% at these temperatures due mainly to the high conductivity in a very thin, very hot surface layer. The transmissivity can be improved by using a composite made of boron nitride and silica.