METAL N-CDTE INTERFACES - A STUDY OF ELECTRICAL CONTACTS BY DEEP-LEVEL TRANSIENT SPECTROSCOPY AND BALLISTIC-ELECTRON-EMISSION MICROSCOPY/

This paper summarises the characteristics of chemically etched CdTe su rfaces obtained by photoluminescence studies and the results of extens ive transport measurements involving metal contacts fabricated on them . Fermi level pinning at five discrete levels; 0.40 +/- 0.02, 0.65 +/- 0.02, 0.73 +/- 0.02, 0.96 +/- 0.04 and 1.18 +/- 0.02 eV has been obse rved. Deep level transient spectroscopy (DLTS) and ballistic electron emission microscopy (BEEM) experiments have been performed on contacts made under the same conditions to compare and confirm these results. DLTS reveal similar values for electron traps in the band gap confirmi ng a relationship between Fermi level pinning and bulk defect levels. BEEM experiments performed on contacts showing I-V barrier heights of 0.96 eV reveal significant planar non-uniformity but confirm 0.96 eV a s the controlling barrier height or charge transport across the juncti on. (C) 1998 Elsevier Science Ltd. All rights reserved.