We propose spin torque nano-oscillators (STNOs) directly integrated on a metal-oxide-semiconductor field-effect-transistor (MOSFET). In this model, we consider an array of STNOs, where the STNOs are synchronized via magnetodipolar interaction. We found that the ac voltage generated by magnetization precession of STNOs directly integrated on a MOSFET can be amplified by the normally-on MOSFET. We also found that the load resistance plays an important role with respect to increasing the output voltage of synchronized STNOs compared to a single STNO and in relation to the gate voltage of the MOSFET. By using numerical calculation, we found that the emitted microwave power is greatly enhanced by amplifying the ac voltage generated by synchronized STNOs. It is anticipated that the results will be verified with existing experimental techniques.