Far Infrared Thermomodulation in Hg0.8Cd0.2Te
The narrow gap semiconductor Hg1−xCdxTe has been extensively studied for its peculiar magnetotransport properties [1–3]. Magnetotransmission in the far infrared was investigated by GOLDMAN et al . It was our intention to study the magnetophotoconductivity in this material in order to observe conduction electron cyclotron resonance (CCR) and possibly impurity cyclotron resonance (ICR). With the laser chopped at a frequency of 20 Hz, a fairly strong signal was observed which contained the expected resonances. However, it was then discovered that this signal persisted when the sample current was turned off, and further investigation revealed that practically no photoconductive response could be detected in these samples in the low-field region (B < 1 T). We have come to the conclusion that the observed signal is due to a modulated thermoelectric voltage resulting from inhomogeneous heating of the sample by the chopped laser radiation.
KeywordsLaser Line Photoconductive Measurement Thermoelectric Voltage Helium Vapor Chopper Frequency
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