We have designed a new type metal-semiconductor-metal structure with InAs self-assembled quantum dots. Hystereses loops were observed in DC current transport. With quantum dots(QDs) directly embedded beneath the GaAs-metal interface, the charge and discharge of electrons in the dots modulate the current to form hysteresis. For a single quantum dot, the charge and discharge can be thought as single-electron processes controlled by applied voltage. In this paper we analyzed the characteristics of charging and discharging processes for the ensemble of QDs as a whole. The discharging process was dominated by the change of tunneling rate with gate voltage. The charging process was controlled by forward current flowing though the diode. The calculated results indicate that the electrons trapped to the ground states of QDs give rise to charging effect. The excited states capture fewer electrons and influence the charging effect weakly.