An Optoelectronic Switch with Multiple Operation States

A Schottky-contact triangular-barrier optoelectronic switch (STOS), grown by molecular beam epitaxy (MBE), has been fabricated. The triangular barrier, formed by inserting an InGaAs delta-doped (delta-doped) quantum well into an n -GaAs layer, provides a potential well for hole accumulation. Due to the hole accumulation in the delta-doped well and the sequential avalanche multiplications in the reverse-biased
pn
and metal-semiconductor (M-S) junctions, a double S-shaped negative-differential-resistance (NDR) 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.