Application of p-n Junction #8211; (i) It can be used as a solar cell. (ii) It is used as rectifier in many electric circuits and as a voltage-controlled oscillator in varactors. (iii) P-N junction diode can be used as a photodiode as the diode is sensitive to the light when the configuration of the diode is reverse-biased. (iv) When the diode is forward-biased, it can be used in LED lighting applications.