Method and apparatus for determining characteristic electrical properties of semi-conducting materials

摘要

PCT No. PCT/DK93/00410 Sec. 371 Date Sep. 1, 1995 Sec. 102(e) Date Sep. 1, 1995 PCT Filed Dec. 7, 1993 PCT Pub. No. WO94/14078 PCT Pub. Date Jun. 23, 1994The present invention relates to a method for determining characteristic electrical properties of semi-conducting materials wherein the time/frequency dependent electrical impedance or admittance of the material is measured. The invention also relates to an apparatus for carrying out the method. A number of bulb and surface parameters characterize the electrical properties of a given piece of material. These parameters include the dielectric constant epsilon of the material, the difference DELTA mu ch in the chemical potential of the bulk of a material and the chemical potential of its surface and/or metal electrode-material surface interface, the density of the majority and minority electrical mobile charge carriers N and Nmin, respectively, in the bulk of the material, the electrical mobility mu of the majority electrical mobile charges in the bulk of the material and the electrical mobility mu min of minority mobile charge carriers, the surface and bulk emission and capture rates E.R. and C.R., respectively, for mobile positive and negative charge carriers characterizing the effect of surface and bulk localized states within the band gap, when they are present, on the electrical transport.