Question

(a) As the bond strength in a material increases we normally find that: the electrical conductivity decreases the electrical conductivity increases the melting point decreases the melting point increases The material becomes more metallic in character (b) In an intrinsic semiconductor: There are absolutely no impurities The electrical conductivity is only determined by thermal excitations The electrical conductivity is independent of the bandgap. There are equal numbers of free electrons and holes (Both electrons and holes will contribute significantly to the electrical current in the material (c) In an extrinsic semiconductor: Othere are equal numbers of free electrons and holes There are impurities to dope the material the carrier concentration will vary exponentially with temperature the carrier concentration will be independent of temperature over a wide temperature range (Both electrons and holes will contribute significantly to the electrical current in the material

Answer 1

(a) electrical conductivity decrease,melting point decreases

(b) all points are correct for intrinsic semiconductor

(C) impurity to dope the material, carrier concet. Vary exponentially with temp., both hole eelctron contribute for current