Sonochemical Synthesis of a Zinc Oxide Core-Shell Nanorod Radial p-n Homojunction Ultraviolet Photodetector

We report for the first time On the growth of a homogeneous radial p-n junction in the ZnO core-shell configuration with a p-doped ZnO nanoshell structure grown around a high qualityunintentionally n-rdoped ZnO nanorod using sonochemistry. The simultaneous decomposition of phosphorous (P), zinc (Zn), and oxygen (O) from their respective,: precursors during sonication allows for the successful incorporation of P atoms-into the ZnO lattice. The as,formed p-n junction Shows a rectifying current-voltage,characteriatic that is consistent With a p-n junction with a, threshold voltage of 1.3 Y. and an ideality factor of 33. The concentration of doping was estimatecl to be N-A = 67 x 10(17) cm(-3),on the p side from the capacitance-voltage measurements: The fabric-ated radial p-n junction demonstrated a record optical responsivity of 9.64 A/W and a noise equivalent power of 0.573 pW/root Hz under ultraviolet illumination, which is the highest for ZnO p-n junction devices.