PT Journal AU Gershenson, EM Gol'tsman, GN Elant'ev, AI Kagane, ML Multanovskii, VV Ptitsina, NG TI Use of submillimeter backward-wave tube spectroscopy in determination of the chemical nature and concentration of residual impurities in pure semiconductors SO Sov. Phys. Semicond. JI Sov. Phys. Semicond. PY 1983 BP 908 EP 913 VL 17 IS 8 DE BWO spectroscopy; pure semiconductors; residual impurities ER