TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Condition: The atomic proportion of barium, relative to the maximum atomic stoichiometric proportion of magnesium in the absence of barium, varies from 0.1-0.4. The atomic proportion of lead relative to the maximum atomic stoichiometric proportion of silicon in the absence of lead varies from 0.1-0.3. The atomic or molecular proportion of the doping material(s) in the composition of matter varies from 10-8 - 10-1. The free charge carrier concentration varies from 1 x 1015 - 5 x 1020 carriers/cm3.Preferred Composition: The composition of matter further comprises additional doping materials. It comprises magnesium silicide, where part of magnesium is replaced by barium, and part of silicon is replaced by lead; or part of magnesium is replaced by beryllium, calcium, strontium and/or barium, and part of the silicon is replaced by germanium, tin, lead, antimony, bismuth, selenium and/or tellurium.Preferred Component: The doping materials or elements are chemically reacted to form compounds with (a) silicon and/or lead; or (b) magnesium and/or barium, prior to their introduction into the host material. It comprises sodium, potassium, rubidium and/or cesium; and phosphorus, arsenic, antimony, bismuth, sulfur, selenium, tellurium, bromine and/or iodine. The additional doping material(s) for the n-type branch of the device comprises nitrogen, phosphorus, arsenic, antimony, bismuth, oxygen, sulfur, selenium, tellurium, chlorine, bromine, iodine, magnesium, barium, lithium, gold, aluminum, indium, iron and/or their compound. The additional doping material(s) for the p-type branch of the device comprises copper, silver, sodium, potassium, rubidium, cesium, boron, silicon, lead and/or their compounds. The doping material is an alloy or solid solution of intermetallic compounds containing magnesium silicide, magnesium plumbide, barium silicide, and barium plumbide of constitutional formula: Ba2rMg2(1-r)Si1-xPbx; Be2uCa2vSr2wBa2zMg2(1-r)Si1-sGeaSnbPbcBieSefTeg; Na2u'K2v'Rb2w'Cs2y'Ba2z'Mg2(ir)Si1-xPbx; Ba2rMg2(1-r)Si1-sPba'Pb'Asc'Sd'Bie'Sf'Seg'TehBriIj; or Na2uK2vRb2wCs2yBa2zMg2(1-r)Si1-sPba'Pb'Asc'Sd' B ie'Sf'Seg'TehBriI j.r = u + v + w + y' + z (represents the sum of the atomic proportions of the elements that replace part of magnesium), particularly 0.1-0.4;(1-r) = 0.6-0.9;(1-x) = 0.7-0.9;x = 0.1-0.3;s = a + b + c + d + e + f + g + h + i + j (represents the sum of the atomic proportions of the elements that replace part of silicon), particularly 0.1-0.3;u, v and w = 0-0.3;u + v + w = 0-0.3;z and a = at least 0.1;a, b, c, d, e, f and g = 0-0.2;a + b + c + d + e + f + g = 0-0.2;c = at least 0.1;u' + v' + w' + y' ; and b' + c' + d' + e' + f' + g' + h + i + j = 10-8-10-1;u', v', w' and y' = 0-0.1; andb', c', d', e', f', g', h, i and j = 0-0.1.