Semiconductor diode - Shockley diode equation

The Shockley ideal diode equation ( also called the diode law) gives the I–V characteristic of an ideal diode. The Shockley ideal diode equation is:

                     
                         

        Where:

                I => is the diode current,

                I_{S =>} is the reverse bias saturation current,

                V_{D =>} is the voltage across the diode,

                V_{T =>} is the termal voltage,

                N => is the ideality factor, depends on the fabrication process and semiconductor material and in many cases is assumed to be approximately equal to 1 (thus the notation n is omitted). By setting n = 1 above, the equation reduces to the Shockley ideal diode equation.

The thermal voltage V_T ( approximately 25.85 mV at 300 K, a temperature close to "room temperature") is commonly used in device simulation software. At any temperature it is a known constant defined by:

        

                              
           where 

                 k => is the Boltzmann constant,

                 T => is the absolute temperature of the p–n junction 
                 q => is the magnitude of charge of an electron.