Which of the following is correct for \(\mathrm{n}\)-type semiconductors?

1.	electron is the majority carriers and trivalent atoms are dopants.
2.	electrons are majority carriers and pentavalent atoms are dopants.
3.	holes are majority carriers and pentavalent atoms are dopants.
4.	holes are majority carriers and trivalent atoms are dopants.

In semiconductors, which of the following gives the law of mass action?
(where symbols have their usual meanings.)
1. \(n_i=n_e=n_h\)
2. \(n_i^2=n_en_h\)
3. \(n_h>> n_e\)
4. \(n_h<<n_e\)

Hole is:

Pure Si at \(500~\text{K}\) has an equal number of electron \((n_e)\) and hole\((n_h)\) concentrations of \(1.5\times10^{16}~\text{m}^{-3}\). Doping by indium increases \(n_h\) to \(4.5\times10^{22}~\text{m}^{-3}\).  The doped semiconductor is of:

Identify the incorrect statement from the following:

Carbon, Silicon, and Germanium atoms have four valence electrons each. Their valence and conduction bands are separated by energy band gaps represented by ${\left({\mathrm{E}}_{\mathrm{g}}\right)}_{\mathrm{C}},{}_{}$ ${\left({\mathrm{E}}_{\mathrm{g}}\right)}_{\mathrm{Si}}$, and ${\left({\mathrm{E}}_{\mathrm{g}}\right)}_{\mathrm{Ge}}$ respectively. Which one of the following relationships is true in their case?

1. ${\left({\mathrm{E}}_{\mathrm{g}}\right)}_{\mathrm{C}}<{\left({\mathrm{E}}_{\mathrm{g}}\right)}_{\mathrm{Ge}}$

2. ${\left({\mathrm{E}}_{\mathrm{g}}\right)}_{\mathrm{C}}>{\left({\mathrm{E}}_{\mathrm{g}}\right)}_{\mathrm{Si}}$

3. ${\left({\mathrm{E}}_{\mathrm{g}}\right)}_{\mathrm{C}}={\left({\mathrm{E}}_{\mathrm{g}}\right)}_{\mathrm{Si}}$

4. ${\left({\mathrm{E}}_{\mathrm{g}}\right)}_{\mathrm{C}}<{\left({\mathrm{E}}_{\mathrm{g}}\right)}_{\mathrm{Si}}$

\(\mathrm{C}\), \(\mathrm{Si}\), and \(\mathrm{Ge}\) have the same lattice structure. Why is the \(\mathrm{C}\) insulator?

Suppose a pure Si crystal has \(5\times10^{28}~\text{atoms m}^{-3}\). It is doped by a \(1\) ppm concentration of pentavalent As. The number of electrons and holes are, respectively: (Given: \(n_i=1.5\times10^{16}~\text{m}^{-3}\))

Why can't we take one slab of p-type semiconductor and physically join it to another slab of n-type semiconductor to get a p-n junction?

The \((V\text-I)\) characteristic of a silicon diode is shown in the figure. The resistance of the diode at \(V_D=-10\) V is:${\mathrm{}}_{}$

     
1. \(1\times10^7~\Omega~\)
2. \(2\times10^7~\Omega~\)
3. \(3\times10^7~\Omega~\)
4. \(4\times10^7~\Omega~\)$\mathrm{}$