4H-SiC Nano-Pillar Avalanche Photodiode With Illumination-Dependent Characteristics

A 4H-SiC nano-pillar-based avalanche photodiode (NAPD) with a separate absorption region and a multiplication region is proposed and its optoelectronic performance is modeled. By properly designing the device geometry and the doping concentration of each layer, the avalanche breakdown voltage
$({V}_{\rm br})$
of the NAPD is found to be dependent of the incident wavelength and power density, which are explained by the band diagrams of 4H-SiC NAPDs.