Semiconductors isotopically enriched

Boron Bromide. Approximately 30% of BBr3 produced in the United States is consumed in the manufacture of proprietory pharmaceuticals (qv) (7). BBr3 is used in the manufacture of isotopically enriched crystalline boron, as a Friedel-Crafts catalyst in various polymerization, alkylation, and acylation reactions, and in semiconductor doping and etching. Examples of use of BBr3 as a catalyst include copolymerization of butadiene with olefins (112) polymerization of ethylene and propylene (113), and IV-vinylcarbazole (114) in hydroboration reactions and in tritium labeling of steroids and aryl... 

The semiconductors that have been the subject of numerous investigations in bulk, alloyed, or nanocrystalline form include Si, Ge, doped diamond, SiC, (B, Al, Ga, In)(N, P, As, Sb), and (Zn, Cd, Hg, Pb)(0, S, Se, Te). Nature has been exceptionally benign in providing NMR-active isotopes at natural abundances exceeding 4% for all of the preceding elements except in the cases of 13C, 33S, and 170, and enrichment with isotopic-labels has become more common. 

---