Synthesis of a high-quality Al-doped CdS/Si nanoheterojunction array and characterization of its electrical and electroluminescence properties

A high-quality nanoheterojunction composed of p-type Si nanoporous pillar array (Si-NPA) and n-type CdS:Al was successfully constructed by growing Al-doped CdS film on a silicon nanoporous pillar array via a simple chemical bath deposition method. The fabricated CdS:Al/Si-NPA nanoheterojunction exhibits a pronounced rectification behavior at a low turn-on voltage of ~ 0.5 V, a relatively high rectification ratio of 217 at ± 1.5 V, and good ideality factors of 0.85 in the low-voltage region and 2.45 in a high-voltage region. The electroluminescence spectra of a nanolight-emitting diode based on the nanoheterojunction are dominated by an intense band-edge emission located at ~ 520 nm under a small forward voltage and free from defect emissions. The intensity increased rapidly with the forward voltage. The emission mechanism and CIE chromaticity coordinates of the electroluminescence spectra were also discussed. The obtained CdS:Al/Si-NPA nanoheterojunction could be used for important applications in nanoscale optoelectronic devices.