A Schottky-contact triangular-barrier optoelectronic switch (STOS)

A Schottky-contact triangular-barrier optoelectronic switch (STOS), grown by molecular beam epitaxy, has been fabricated. The triangular barrier, formed by inserting an InGaAs delta-doped (/spl delta/-doped) quantum well into an n/sup -/-GaAs layer, provides a potential well for hole accumulation. Due to the hole accumulation in the /spl delta/-doped well and the sequential avalanche multiplications in the reverse-biased p-n and metal-semiconductor junctions, a double S-shaped negative-differential-resistance phenomenon is observed in the current-voltage (I-V) characteristics. The STOS shows a flexible optical function related to the triangular barrier height controllable by incident light. The multistate is switchable by both optical and electrical inputs.