ACOUSTIC AMPLIFICATION AND ELECTRON MOBILITY IN LITHIUM AND SODIUM DOPED CADMIUM SULFIDE.

The acoustic amplification, drift mobility and Hall mobility were measured in thirteen cadmium sulfide crystals to determine the effect of impurities on these properties. Ten of the measured crystals were grown doped with lithium, sodium or a combination of both sodium and lithium and three crystals were grown undoped. The undoped crystals have a maximum acoustic gain of about 70 dbcm, a Hall mobility of 170 sq cmvolt-sec and a drift mobility of 160 sq cmvolt-sec. The lithium doped crystals have a maximum gain of about 100 dbcm, a Hall mobility of 300 sq cmvolt-sec and a drift mobility of 100 sq cmvolt-sec. The sodium doped crystals have a maximum gain of 3 dbcm, a Hall mobility 100 sq cm volt-sec and a drift mobility of 50 sq cmvolt-sec. The sodium-plus-lithium doped crystals have a maximum gain of about 25 dbcm, a Hall mobility of 200 sq cmvolt-sec and a drift mobility of 150 sq cmvolt-sec. The measurements indicate that impurities in the crystal can either increase or reduce the acoustic amplification and impurities increase electron trapping within the crystal, thus reducing the drift mobility. Author