Question

(a) Write the values of axial angles for hexagonal crystal system.
(b) Which type of semiconductor is obtained by doping boron with silicon? Explain.

Answer 1

(a) The values of axial angles for hexagonal crystal system are $\alpha =\beta ={90}^o;\gamma ={120}^o$
(b) n- type of semiconductor is obtained by doping boron with silicon. This is due to presence of free electron. boron is trivalent and silicon is tetravalent. Thus 1 electron per Si atom remains free.