Photoluminescene and Pair Spectrum in Boron Phosphide

The photoluminescence spectrum of BP was measured at 1.8, 5.0, and 77\ifmmode^\circ\else\textdegree\fi{}K. The 77\ifmmode^\circ\else\textdegree\fi{}K spectrum consists of four bands, one of which appears to be caused by inclusions of phosphorus atoms. At 1.8\ifmmode^\circ\else\textdegree\fi{}K, in addition to the four bands, a donor-acceptor pair spectrum was observed (type-II spectrum) similar to that observed by Hopfield and co-workers in GaP.