Fabrication of CdS Nanorods on Si Pyramid Surface for Photosensitive Application

It is the first time that cadmium sulfide (CdS) nanorods have been fabricated on silicon (Si) pyramid surface by the hydrothermal reaction method. In our work, the Si pyramid morphology is able to increase the adhesion between the CdS seed layer and Si wafer. Hence, it is critical for CdS nanorods to grow successfully. During the fabrication process, the glutathione is used as the complexing agent for the formation of the CdS nanorods. By continuously adjusting the experimental conditions, the thickness of the CdS seed layer, the concentration of the glutathione, and the temperature and time of the hydrothermal reaction, the optimal condition for CdS nanorods growth on Si pyramid surface is 80 nm seed layer, 0.2-0.3 mmol glutathione, 200 °C, and 1.5 h. The Cd and S elements have a ratio of 1:1.03 from the energy-dispersive spectroscopy test, which is in agreement with the stoichiometric composition of CdS. The CdS nanorods have a bandwidth of 2.22 eV through the optical absorption spectra. The photosensitivity response test results reveal these CdS nanorods on the Si pyramid structure have an obvious photosensitive effect. From the analysis, the CdS nanorods can grow on any morphological Si surface if the adhesion between the CdS seed layer and the Si surface is strong enough.