Question

For Si single crystals: ni = 1.45 x 1010 cm-3 ; electron mobility µn = 1400 cm2 V-1 s-1 ; hole mobility µp = 450 cm2 V-1 s-1 . (a) A single crystal of Si is highly doped with B (a p-type dopant). It has a measured resistivity of 1.5 x 10-3 W-cm.

a) What are the free hole (p) and free electron (n) concentrations (in carriers/cm3 ) in the material?

b) If a quantum dot (diameter = 5 nm) is made from the above silicon wafer, how many dopant atoms are in a single quantum dot? Assume that the quantum dot is spherical, so the volume of the dot, V = 4/3 pr 3 , where r = dot radius = 1/2 dot diameter.

c) If a quantum dot (diameter = 5 nm) is made from the above silicon wafer, how many silicon atoms are in a single quantum dot? Assume that the quantum dot is spherical, and the density of silicon is 2.33 g/cm3 .

Answer 1