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In a Hall effect measurements in magnetic field with induction B= 5.0kG the transverse electric field strength in an impurity-free germanium turned out be eta=10 times less than the longitudinal electric field strength. Find the difference in the mobilities of conduction electrons and holes in the given semiconductor. |
Answer» SOLUTION : If an electric field `E_(x)` is present in a sample containing equal AMOUNTS of both electrons and holes, the two drift in opposite directions. In the presence of a magnetic field `B_(Ƶ)=B` they SET up Halll voltage in opposite directions. The net Hall electric field is GIVEN by `E_(y)=(v_(x)^(+)-v_(x)^(-))B` `=(v_(x)^(+)-v_(x)^(-))B` `=(u_(0)^(+)u_(0)^(-))E_(x)B` But `(E_(y))/(E_(x))=(1)/(ETA)` Hence `|u_(0)^(+)-u_(0)^(-)|=(1)/(etaB)` Substitution gives `|u_(0)^(+)-u_(0)^(-)|= 0.2m^(2)//"volt-sec"` |
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