Synthesis of Si Nanosheets by a Chemical Vapor Deposition Process and Their Blue Emissions

Abstract

We synthesized free-standing Si nanosheets (NSs) with a thickness of about <2 nm using a chemical vapor deposition process and studied their optical properties. The Si NSs were formed by the formation of frameworks first along six different <110> directions normal to [111], its zone axis, and then by filling the spaces between the frameworks along the <112> directions under high flow rate of processing gas. The Si NSs showed blue emission at 435 nm, and absorbance and photoluminescence (PL) excitation measurements indicate that enhanced direct band transition attributes to the emission. Time-resolved PL measurement, which showed PL emission at 435 nm and a radiative lifetime of 1.346 ns, also indicates the enhanced direct band gap transition in these Si NSs. These outcomes indicate that dimensionality of Si nanostructures may affect the band gap transition and, in turn, the optical properties.

Hydrogen and fluorine co-decorated silicene: A first principles study of piezoelectric properties

“…Showing a contraction of the bond compared with bulk Si, the optimized Si-Si bond length is calculated to be 2.28 Å , which is in good agreement with previous calculations. [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] Unlike planar graphene, silicene-in agreement with previous calculations-has a low buckled structure with the buckling parameter, 22,62 h ¼ 0.46 Å . The buckling parameter is the distance between two parallel silicon planes.…”

“…(14) and f is the applied field. Note that a similar definition is used to predict piezoelectric coefficients in organic 79 Now, we are going to develop a formula to calculate d 33 from energy and e 33 using Taylor expansion.…”

“…8 Consequently, a great deal of effort has been devoted to synthesizing silicene. [9][10][11][12][13][14] As a result, by providing direct evidence of the presence of two-dimensional silicene, recent successes of silicene fabrication through epitaxial growth on metal (Ag, [9][10][11] Ir, 12 and ZrB 2 13 ) substrates in the form of nanoribbons and nanosheets are promising for future works. However, metallic substrates disrupt silicene's electrical properties and make it difficult to compare experimental data with theoretical predictions.…”

Silicon-based nanosheets synthesized by a topochemical reaction for use as anodes for lithium ion batteries

“…For example, Si thin films, typical 2D materials, show better cycling performance compared to powder-based anodes. Other 2D Si-based materials have also been fabricated, including nanoribbons [26], thin flakes [27,28], and nanosheets [29][30][31]. However, the main disadvantage of 2D Si-based materials is that their preparation methods are complicated, involving rigorous reaction conditions (high temperature and/or high vacuum), high cost, toxic and/or inflammable reactants, complicated reaction processes and low productivity.…”

Role of oxygen concentration distribution and microstructure in luminescent properties of laser-irradiated silicon

“…Silicon-based semiconductor and optoelectronic devices play an increasingly important role in the field of microelectronics and optics [1][2][3][4]. However, the unmodified silicon is a poor light emitter due to its indirect band gap which greatly limits the application and development of these devices.…”