Phase Controlled Growth of Cd3As2Nanowires and Their Negative Photoconductivity
The bottom-up synthesis process often allows the growth of metastable phase nanowires instead of the thermodynamically stable phase. Herein, we synthesized Cd3As2 nanowires with a controlled three-dimensional Dirac semimetal phase using a chemical vapor transport method. Three different phases such as the body centered tetragonal (bct), and two metastable primitive tetragonal (P42/nbc and P42/nmc) phases were identified. The conversion between three phases (bct → P42/nbc → P42/nmc) was achieved by increasing the growth temperature. The growth direction is  for bct and P42/nbc and  for P42/nmc, corresponding to the same crystallographic axis. Field effect transistors and photodetector devices showed the nearly same electrical and photoelectrical properties for three phases. Differential conductance measurement confirms excellent electron mobility (2 × 104 cm2/(V s) at 10 K). Negative photoconductance was first observed, and the photoresponsivity reached 3 × 104 A/W, which is ascribed to the surface defects acting as trap sites for the photogenerated electrons.
Publication Source (Journal or Book title)
Park, K., Jung, M., Kim, D., Bayogan, J., Lee, J., An, S., Seo, J., Seo, J., Ahn, J., & Park, J. (2020). Phase Controlled Growth of Cd3As2Nanowires and Their Negative Photoconductivity. Nano Letters, 20 (7), 4939-4946. https://doi.org/10.1021/acs.nanolett.0c01010