Electrical Conductivity of n‐InSe Single Crystals in Strong Electric Fields

The electrical conductivity of n‐InSe single crystals is studied under pulsed operation conditions in electric fields up to 4 × 104 V/cm within the temperature range 140 to 300 °K. For fields exceeding 900 V/cm Ohm's law is violated and the electrical conductivity increases with field strength according to Frenkel's law σ = magnified image , where β is proportional to 1/T in the range 140 to 300 °K. From the temperature dependence of β = magnified image the electronic component of the dielectric constant is found to be 3 to 4. A breakdown field of ≈︁ 106 V/cm is determined by extrapolating the lg σ = magnified image straight line. The carrier activation energy of 0.18 eV obtained from the temperature dependence of the conductivity in weak fields, decreases with incrasing field strengths. By extrapolating the lg σ = magnified image straight lines a metallization temperature of 16660 °K is found which gives an energy gap of 1.38 eV at absolute zero.