Synthesis, structure, and optical properties of nanopowders CdS: xAl (x=0, 1, 5, 10, 15 and 20%) via the sol–gel technique

Abstract

The nanocrystalline Al-doped CdS semiconductors were produced accurately by the sol-gel calcination process. The aluminum was added with different percent's (0, 1, 5, 10, 15, and 20 wt%) to the synthesized CdS. Both FT-Raman analysis and UV-VIS-NIR absorption measurements were utilized to characterize the studied semiconductors' structural and optical characteristics. The detected X-ray diffraction (XRD) patterns of the prepared CdS present a polycrystalline structure, and Al-doping does not significantly impact this range. Optical bandgaps were determined for undoped and Al-doped CdS, showing a significant change with the percentage of Al-dopants. With increasing Al-doping up to (20 percent), the optical bandgap for CdS (2.38 eV) grows to reach (2.47 eV) and the allowed transitions were found to be direct for the investigated samples. The blue shift may be the reason for the optical bandgap variations. Scanning Electron Microscope (SEM) micrographs were performed to establish the Al-doped CdS nanostructure to identify the morphological characteristics.

Effect of Order of Reagents Addition on Optical and Structural Properties of CdS Quantum Dot Prepared by Chemical Bath Deposition Technique

“…They are semiconductors with electronic properties closely related to the size and shape of the individual crystals. This implies that their particle sizes are similar to those of the exciton Bohr radius or the de Broglie wavelength [8,9]. QDs have attracted considerable attention from researchers in nanotechnology.…”

“…It is also very important as a window layer in the highly efficient polycrystalline Copper Indium Gallium Sulfide (CIGS) and copper indium gallium telluride, (CIGT) [3,4], which are n-type semiconductors with wide direct band gap energy and exist in two crystalline phases of hexagonal wurzite and cubic zinc-blend structures with unique high electron affinity [5]. CdS QDs have been used as n-type materials for the formation of a heterojunction in some photovoltaic systems, such as copper indium selenide (CIS) [6], copper indium gallium diselenide (CIGD) [7], and cadmium telluride (CdTe) [8].Quantum dots (QDs) are semiconductor nanocrystals with a typical size of 2-10 nm and whose electrons are confined in three directions. They are semiconductors with electronic properties closely related to the size and shape of the individual crystals.…”