A novel multistate S-shaped negative differential conductivity (NDC) δ-doped superlattice structure with long period (Zp = 600 A) is observed and investigated. The multi-state NDC originates from a sequential sub-avalanche multiplication in the superlattice periods. Three different superlattices, i.e. one-period, three-period, and nine-period δ(n+)-i-δ(p+)-i δ-doped superlattices, were used. A different number of S-shaped NDCs are exhibited in each superlattice. An intersting hysteresis phenomenon was also apparent in the nine-period superlattice structure. It was attributed to the existence of heavy 'trapped' holes.
All Science Journal Classification (ASJC) codes