# Thermal voltage of Ge diode

What is the thermal voltage of a Ge diode?I know for a silicon diode is about 26mV at room temperature.

I have this circuit:

simulate this circuit – Schematic created using CircuitLab

and a set of equation where X = Current through the diodes , Y = Voltage drop of Si diode and Z = Voltage drop of Ge diode:

x = (3-y-z)/1000

x = (10^-12)*(e^(y/0.026)-1)

x = (10^-9)*(e^(z/Vt(Ge))-1)

and I need it (at room temperature) so help really appreciated.

$$V_T = \frac{kT}{q},$$
where $$\k\$$ is the Boltzmann constant, $$\k = 1.380649 × 10^{-23}\ \mathrm{J}·\mathrm{K}^{-1},\ T\$$ is the temperature, and $$\q\$$ is the electron charge, $$\q=1.602176634 × 10^{-19}\ \mathrm{C}.\$$