In this paper we present the results of investigation of heterostructures with an array of InAs quantum dots grown on GaAs substrates with GaAs and AlGaAs front barriers for high-speed near-IR photodetectors. The thickness of the barrier layers did not exceed 30 nm. It is shown that the ion-beam deposition method makes it possible to grow quantum dots with lateral dimensions up to 30 nm and 15 nm height. The spectral dependences of the external quantum efficiency and dark current-voltage characteristics are investigated.