CHARACTERISTICS OF THE TUNNELING ACROSS SCHOTTKY BARRIERS MADE OF NARROW-GAP SEMICONDUCTOR P-TYPE HG1-XCDXTE

The electrophysical characteristics of Pb(Sn)-p-Hg, CdxTe Schottky barriers [x = 0.2-0.4, N(A)-N(D) = (0.2-10) X 10(15) cm-3] with a near-unity nonlinear coefficient were investigated at temperatures 4.2 < T < 250 K. For all the compositions and dopant concentrations the Fermi level on the semiconductor surface was pinned at phi0 approximately 2E(g)/3 from the top of the valence band. The experimental results were described satisfactorily by the two-band Kane approximation for the dispersion law only if an allowance was made for the simultaneous occurrence (frequently in the same interval of temperatures T) of the following processes: interband tunneling, tunneling involving deep levels, thermal-field emission, and above-barrier mechanism. The anomalies of the temperature dependences of the reverse tunnel current were explained by the temperature dependences of the effective mass and of phi0 at low values of T, and by predominance of the interband thermal-field emission at high temperatures T.