Light emission and negative differential conductance of n-type nanoporous silicon with buried p-layer assistance

Abstract

The light-emission and current-voltage properties of n-type nanoporous silicon (n-NPS) with a hole assistance of buried p layer are explored. The influences of anodic current density on the formation, morphology, and properties of n-NPS are measured. Such n-NPS films have nanoscaled pores and high-aspect-ratio pillars. Since the anisotype junction is forward biased during the anodization process, many holes can drift straightupward from p layer and participate in the electrochemical reaction. At room temperature, high peak-to-valley current ratios of about 117.3 can be obtained in negative difference conductance region as well as strong visible light emissions are clearly observed under ultraviolet excitation.