We have investigated the transport properties of a metal-semiconductor-metal structure containing multi-layers of InAs quantum dots from 77 K to room temperature. Three distinct phenomena are observed in the current voltage( I-V ) curves:the hysteresis loops, current jumps and voltage offsets. Because of the coupling between the multi layered quantum dots, the devices made of these quantum dots exhibit much more complicated phenomenon than the devices containing single-layer quantum dots. The devices may undergo many metastable states and relaxation processes. These processes would induce current jump structures and noise in the I-V curve.