HW Check: Categorize materials as n or p type semiconductors: a. Zn doped GaAs >>> p-type b. In 1+x As 1-x >>> n-type c. Li 0.05 Cu 0.95 O >>> p-type d. WO 2.999 >>> n-type Solution Answer - a.Zn doped with GaAs -It form p type semiconductors. As zinc is Zn +2 in ionic state. Zn have 2 electron in valance shell. b. In 1+x As 1-x it forms n-type semiconductor because ln(1+x) have more electrons then As(1-x) . c. Li 0.05 Cu 0.95 O is p-type as cu forms cu 2+ , During conduction d. WO 2.999 Here the conncentration of O is greater than W, hence it forms n-type semiconductor. All answer correct. .