The Research Of Optical And Electrical Properties Based GaSb And Sb₂A₃ Nanowire Photodetectors

As one of the important III-V compound semiconductor material, gallium antimonide(GaSb) with high hole mobility(850 cm2/Vs) and suitable band gap(0.7 eV) is of interest for a variety of applications, including high-speed electronics, especially infrared optoelectronics. GaSb nanowires based photodetector shows characteristics of high performance in sensitivity and detectivity while detecting visible and infrared light. As another Sb based compound, Sb2S3 nanowire is also good optoelectronic material. With suitable band gap of 1.5~2.2 e V, it can detect light from ultraviolet to infrared in wide spectral region. As the performance of Sb2S3 device is not as good as GaSb, so some improvements in structure has been made to optimize performa nce. The main contents are described as follows:(1) The GaSb nanowires were prepared via a chemical vapor deposition(CVD) method on Si substrate and then single GaSb nanowire based photodetector was fabricated on Si/SiO2 substrate. Through the test, the device exhibited high photoresponse, fast response speed and stable switching characteristic. Under illumination of ?= 700 nm and light intensity P = 0.2 mW/cm2, the as-fabricated rigid device showed responsivity of 295 A/W and response time of 80 ms. While the photodetector was fabricated on flexible polyethylene terephthalate(PET) substrate, it had lower dark current and showed good performance, which was comparable to the rigid one. Under the same condition, the detectivity of flexible device reached 9.7×109 jones and the corresponding noise equivalent power reached 2.0×10-12W/Hz1/2.(2) The Sb2S3 nanowires were prepared through the same simple CVD method and then as-prepared nanowires were decorated by Au nanoparticles. At the same time, Sb2S3 nanowires based Au nanoparticles decorated photodetector was fabricated on Si/SiO2 substrate and not decorated photodetector was also made to do a comparsion. The results showed that Au nanoparticles decoration made photocurrent enhanced evidently and the response time reduced. We made some scientific explanation to these results. In addition, the research on the photodetector o n flexible PET substrate exhibited that Au nanoparticles decoration improved the performance similarly. The responsitivity to white light was changed from 4.9 A/W to 20 A/W.