The purpose is to study the preparation of p type polyaniline (PANI) nanowire array and the fabrication of high performance UV photodetector with p-n junction based on p type polyaniline nanowire array and n type silicon.High-density polyaniline nanowire array was fabricated by using a layer of manganese dioxide as seed layer which was prepared by spin-coating method on the silicon substrate.The influence of different conditions on the morphology of polyaniline was discussed

and the growth mechanism of polyaniline nanowire array was revealed.It was found that polyaniline nanoparticles were priorly generated on the manganese dioxide seed layer with the oxidation of manganese dioxide seed layer to aniline in solution.The polyaniline nanoparticles grew vertically when another oxidant of ammonium persulfate(APS)was added into the solution

and high-density p type polyaniline nanowire array was obtained.Furthermore

high performance UV photodetector was fabricated with fast photoresponse

short recovery time and good stability based on the p-n junction of p type polyaniline nanowire array and n type silicon.When the bias voltage was 0 V

photocurrent was 9.210-8A.And the intensity of photocurrent increased greatly when the bias voltage was improved.When the bias voltage arrived at 5 V

the photocurrent was improved to 3.210-5A which was 1000 times higher than that with 0 V bias voltage.