Infrared Lateral Photoconductivity of InGaAs Quantum Dots: the Temperature Dependence

We report the temperature dependence of lateral infrared photoconductivity in multilayer InGaAs/GaAs heterostructures with selectively doped quantum dots fabricated by metalorganic chemical vapor deposition. Two spectral lines of normal-inci dence intersubband photoconductivity (90 meV and 230 meV) and a line originating from interband transitions (930 meV) were observed. The photoconductivity line 230 meV is revealed up to the temperature 140 K. The long-wavelength photoconductivity line 90 meV is quenched rapidly at the temperature 30÷40 K owing to redistribution of photoexcited carriers between small and large dots. The obtained results confirm the hypothesis about bimodal distribution of quantum dot sizes.