Are voltages accross junction diodes independent of temperature?

Question

i mean we know that silicon diode has 0.7V voltage drop is it varies with the temperature?

Answer 1

It changes. Its fairly linear, and can be used as a temperature sensor. Unfortunately, the voltage varies from one diode to another, so you have to calibrate each diode. The slope is pretty repeatable, if I recall correctly, its pretty close to 2mV/degree C for silicon p-n junctions.

We used this property to measure semiconductor package thermal resistance back in the 1980's.

Answer 2

diode forward voltage goes down by 2 mV to 2.2 mV per degree C. Note that it is reversed in slope.

Fairly stable, it can be used as a thermometer.