$P$-type semiconductors are made by adding which impurity element?

In a $p$-type semiconductor,which of the following statements is true?

$A$ crystal of intrinsic silicon at room temperature has a carrier concentration of $1.6 \times 10^{16} / m^3$. If the donor concentration level is $4.8 \times 10^{20} / m^3$, then the concentration of holes in the semiconductor is

To obtain $P$-type $Si$ semiconductor,we need to dope pure $Si$ with

When the conductivity of a semiconductor is only due to breaking of covalent bonds, the semiconductor is called

Which of the following statements is incorrect?