CHARGE-CARRIER EXCLUSION AND ACCUMULATION INTENSIFIED BY OHMIC CONTACTS

The effect of the high generation-recombination power of an ohmic cont act (S contact) on exclusion-accumulation processes in structures with an antiblocking contact (asymmetric structures of the type p(+)-p-S) was studied theoretically and experimentally. It is shown that, in con trast to the ordinarily studied symmetric structure p(+)-p-p(+), the a symmetric structures, which is being studied, forms a region of accumu lation or exclusion, depending on the direction of the current. The no nequilibrium carrier density in the accumulation layer is much higher while the exclusion region is longer than in the symmetric structure. A density n 100 times higher than the equilibrium value n(o) was obtai ned experimentally for Ge at 300 K. The length of the exclusion region reached 96% of the sample length. Applications of structures with ant iblocking and ohmic contacts based on narrow-gap materials are propose d. (C) 1998 American Institute of Physics. [S1063-7826(98)02505-8].