In a first aspect, a first method of adjusting capacitance of a semiconductor device is provided. The first method includes the steps of (1) providing a transistor including a dielectric material having a dielectric constant of about 3.9 to about 25, wherein the transistor is adapted to operate in a first mode to provide a capacitance and further adapted to operate in a second mode to change a threshold voltage of the transistor from an original threshold voltage to a changed threshold voltage such that the changed threshold voltage affects a capacitance provided by the transistor when operated in the first mode; and (2) employing the transistor in a circuit. Numerous other aspects are provided.