Potential well

About: Potential well is a research topic. Over the lifetime, 1430 publications have been published within this topic receiving 30812 citations.

Synthesis and characterization of graphene quantum dots and their size reduction using swift heavy ion beam

Abstract: Graphene quantum dots (GQDs) are nanosized fragments of graphene displaying quantum confinement effect. They have shown to be prepared from various methods which include ion beam etching of graphene. However, recently the modification of the GQDs has garnered tremendous attention owing to its suitability for various applications. Here, we have studied the effect of swift ion beam irradiation on the properties of GQDs. The ion beam treatment on the GQDs exhibited the change in observed photoluminescence of GQDs as they exhibited a blue luminescence on excitation with longwave UV (≈365 nm) due to the reduction in size and removal of the ethoxy (–C–O–C–) groups present on the quantum dots. This was confirmed by transmission electron microscopy, particle size analysis, and Fourier transform infrared spectroscopy.

Pulsed Laser Deposition of Silicon Nanostructures

Abstract: Silicon nanostructures embedded in an amorphous matrix have been synthesized by Pulsed Laser Deposition (PLD) at room temperature. The structural and optical properties of the materials were tailored by varying deposition parameters; attention has been devoted to the nanoscale morphology of the Si layers which has been varied from compact to open-porous by changing background gas (Ar) pressure (1-100 Pa). An adopted simple-minded strategy of a compact Si layer deposited on top of nanostructured layers showed to reduce quite successfullyex-situ oxidation. Raman spectroscopy suggests that as deposited samples are mainly constituted by amorphous silicon with nanocrystals (NCs) inclusions. The results indicate that the average size of the Si NCs varies in the range 2–6 nm. Photoluminescence (PL) responses are found to be strictly dependent on morphology and strengthen up the idea of the quantum confinement effect in the obtained nanostructured material. The results are interpreted in terms of particle size distribution, crystallinity and partial surface oxidation of the silicon nanostructures.

Crystal orientation dependence of alternating current photo-assisted (ACPEC) porous silicon for potential optoelectronic application

Abstract: Porous silicon (PS) was successfully fabricated using an alternating current photo-assisted electrochemical etching (ACPEC) technique. This study aims to compare the effect of different crystal orientation of Si n(100) and n(111) on the structural and optical characteristics of the PS.,PS was fabricated using ACPEC etching with a current density of J = 10 mA/cm2 and etching time of 30 min. The PS samples denoted by PS100 and PS111 were etched using HF-based solution under the illumination of an incandescent white light.,FESEM images showed that the porous structure of PS100 was a uniform circular shape with higher density and porosity than PS111. In addition, the AFM indicated that the surface roughness of porous n(100) was less than porous n(111). Raman spectra of the PS samples showed a stronger peak with FWHM of 4.211 cm−1 and redshift of 1.093 cm−1. High resolution X-ray diffraction revealed cubic Si phases in the PS samples with tensile strain for porous n(100) and compressive strain for porous n(111). Photoluminescence observation of porous n(100) and porous n(111) displayed significant visible emissions at 651.97 nm (Eg = 190eV) and 640.89 nm (Eg = 1.93 eV) which was because of the nano-structure size of silicon through the quantum confinement effect. The size of Si nanostructures was approximately 8 nm from a quantized state effective mass theory.,The work presented crystal orientation dependence of Si n(100) and n(111) for the formation of uniform and denser PS using new ACPEC technique for potential visible optoelectronic application. The ACPEC technique has effectively formed good structural and optical characteristics of PS.