Physics thermoelectricity related plot

Why, I cannot see the plot when I type of the following code:

In[56]:= << PhysicalConstants` (* tick mark used, next to number 1 \
key*)

In[57]:= BoltzmannConstant
Out[57]= (1.38065*10^-23 Joule)/Kelvin

In[58]:= Vt[T_] := BoltzmannConstant*T/ElectronCharge
In[111]:= Vt[1]

Out[111]= (0.0000861734 Joule)/(Coulomb Kelvin)
In[60]:= Ies = 10^-9 (*  Unita A Transistor reverse current *)

 Ic[Vbe_, T_] := Ies*(Exp[Vbe/(Vt[T])] - 1)
In[116]:= Plot[Ic[Vbe, 273], {Vbe, 0, 0.7}]

Please edit your TITLE and make it meaningful and describing your question.

Please read the rules of this forum - especially about code formatting - then edit your post and format code properly.

You might edit in a little note saying what version of Mathematica you are using. The way units were handled was completely changed starting with version 9 and examples for a version you don’t have won’t be helpful.

If you are using version 9 or later then you might compare this with what you showed. And watch for the missing _ in your Ic definition.

In[1]:= boltz = UnitConvert[Quantity["BoltzmannConstant"], "Joules"/"Kelvins"]

Out[1]= Quantity[1.38065*10^-23, ("Joules")/("Kelvins")]

In[2]:= echarge = UnitConvert[Quantity["ElectronCharge"], "Coulombs"]

Out[2]= Quantity[1.6021766*10^-19, "Coulombs"]

In[3]:= Vt[T_] := boltz*T/echarge

In[4]:= Vt[1]

Out[4]= Quantity[0.000086173, ("Joules")/("Coulombs" "Kelvins")]

In[5]:= Ies = 10^-9 (*Unita A Transistor reverse current*)

Out[5]= 1/1000000000

In[6]:= Ic[Vbe_, T_] := Ies*(Exp[Vbe/QuantityMagnitude[Vt[T]]] - 1)

In[7]:= Ic[Vbe, 273]

Out[7]= (-1 + E^(42.5074 Vbe))/1000000000

In[8]:= Plot[Ic[Vbe, 273], {Vbe, 0, 0.7}]

If you insert PlotRange->All just before the final closing ] of that Plot then you will be able to see the current out to 0.7 volts.

Please check this carefully and point out any mistakes that you see.
Thank you