Fabrication and characterization of ZnO nanocrystal/p-Si heterojunction diode

Zinc oxide (ZnO) nanocrystals were fabricated on p-type silicon (p-Si) wafers. The morphologies, crystalline structure and absorption spectrum were investigated by field-emission scanning-electron microscopy (FESEM), X-ray diffraction (XRD), and ultraviolet–visible (UV–Vis) spectroscopy, respectively. The results showed the agglomerated nanocrystals contained a great number of irregularly shaped particles with a wurtzite structure. Also, the current–voltage (I–V) characteristics and several key parameters of the Al/p-Si/ZnO nanocrystals/Ag device in the dark and under ultraviolet (UV) light illumination were investigated. The results showed that the device exhibited good rectifying behaviours in the dark and under UV light illumination. The maximum rectifying ratio, turn on voltage and ideality factor of the device in the dark were 1.15 × 10 4 , 1.0 V and 2.36, respectively. In addition, under 365 nm UV light illumination, the rectifying ratio and photoresponsivity of the device were 2.54 × 10 3 and 2.75 × 10 −4 A/W, respectively.