The effect of high-frequency sonication on charge carrier transport in LPE and MBE HgCdTe layers

A systematic study of mercury cadmium telluride thin films subjected to high-frequency sonication was carried out. Photoconductivity spectroscopy and the Hall effect technique were used. The charge carrier transport parameters were determined from the Hall coefficient and conductivity measurements. The best agreement between experiment and calculation was obtained assuming that the layer with low-mobility electrons was formed as a consequence of the sonication. It was also determined that the parameters of HgCdTe thin films grown by MBE on GaAs substrates are stable to ultrasonic influence, whereas for HgCdTe thin films grown by LPE on CdZnTe substrates the conductivity-type conversion stimulated by sonication takes place. Substrate properties have been observed to play a significant role for the stability of the HgCdTe epilayers. The phenomenon of the negative differential resistance was detected during the sonication of the n-type HgCdTe bulk crystal.