Semiconducter What is conductor? Conductors are materials that permit electrons to flow freely from particle to particle. Ex : iron,coper,silver etc. Intrinsive semiconder natural/pure/without any impurity Intrinsic semiconductors are those made from the purest form of semiconductor material. 1. silicon(z=14) Valency =4 2. germanium(z=32) Valency =4 #Both have 4 valence electrons. #All 4 valence electron are involved in covalent bond in formation in silicon and germanium. Eg=1.1ev Si Eg=0.72ev Ge pure 1. at absolute temp. 0 kelvin there are no free electrons . 2. as all the valence electron are involved in covalent bond . semiconductor will behave like an insulator at 0 kelvin Providing external energy in the form of heat (300k) e Hole: vacancy due to thermally generated free electron holes are positively charged - => e-+ .