Bulk-barrier and potential-spike height effects on characteristics of npn heterostructural optoelectronic switches

GaAs/InGaP and AlGaAs/GaAs/InAlGaP npn heterostructural optoelectronic switches (HSOSs) have been fabricated to demonstrate the bulk-barrier and potential-spike height effects on switching. It is seen that the illumination decreases the switching voltage V_S and increases the switching current I_S in the GaAs/InGaP HSOS characteristics. But in the AlGaAs/GaAs/InAlGaP HSOS, the V_S and I_S present contrary trends. These characteristics variation differences in the two HSOSs are mainly because of the photogenerated carriers that affect the bulk-barrier and potential-spike heights.