a potential difference of 2 5 V is applied across the faces of a germanium crystal plate The face - Physics - Semiconductor Electronics Materials Devices And Simple Circuits

Question

a potential difference of 2 5 V is applied across the faces of a
germanium crystal plate The face area of the crystal is 1 cm2 and
it's thickness is 1 0 mm The free electron conc in germanium is 210
19 /m3 and the electron and holes mobilities are 0 33 m2/Vs and 0
17 m2/Vs respectively The current across the plate will be

Ved Prakash Lakhera · Accepted Answer

The volume of germanium plate=Area×thickness=1×10-4×1×10-3=1×10-7mTherefore total number of free electrons in the plate=2×1019×10-7=2×1012Thus  charge on these electrons=ne=2×1012×1
6×10-19=2×10-7CThe resistivity ρ=1neμe+μh=13
2×10-70 33+0 17=1071 6=0
625×107ohm-metreThe resistance R=ρlA=0
625×107×10-310-4=0
625×108ohmSo the current through the germanium plate I=VR=2
50 625×108=4×10-7A