Bolometric effect in the far-infrared response of a conducting layer on a semi-insulating substrate

Far-infrared photoconductivity measurements were performed on In-doped CdTe layers grown on a semiinsulating GaAs substrate. A thin layer of ZnTe was usually grown between the CdTe and GaAs. The photoconductivity spectra exhi bited an extremely rich structure. Some of the peaks were identified as int radonor transitions, while others, whose energy does not change with magnet ic field, were more difficult to allocate. To explain the spectra, calculat ions of the complete far infrared optical response of the CdTe/ZnTe/GaAs st ructures were performed and compared with the photoconductivity results. Th e mathematical model was formulated in terms of the dynamic dielectric func tion of the structure, and calculations were done by means of the transfer matrix method. A physical model is proposed, linking the absorption of ligh t by the crystal lattice with the observed photoconductivity. The same effe ct is observed in similar measurements performed an other materials, such a s GaN and GaAs. [S0163-1829(99)06239-6].