Stability, local structure and electronic properties of borane radicals on the Si(1 0 0) 2 × 1:H surface: A first-principles study

Phys. Chem. Chem. Phys.

et al. 2016

In this paper the short and long range order in In0.483Ga0.517P thin films is investigated by solid-state Nuclear Magnetic Resonance (NMR) spectroscopy. To this end two samples were grown on a GaAs substrate by metal-organic vapor phase epitaxy at two different growth-pressures. From band gap energy measurements, CuPt long range order parameters of SCuPt = 0.22 and 0.39 were deduced, respectively. In the (31)P spectrum five resonances are observed corresponding to the five possible P(GanIn4-n), n = 0-4, coordinations whose relative intensities correspond to the order in the material, but the intensity variations for order parameters between 0 and 0.5 are minimal. (69)Ga, (71)Ga and (115)In (MQ)MAS spectra were acquired to analyze the quadrupolar and chemical shift distributions related to the (dis)order in these materials in more detail. All these spectra clearly reflect the disorder in the sample and do not show the presence of highly ordered domains. The difference in the order parameter in the sample is not clearly reflected in the spectra. (31)P chemical shifts were calculated using Density Functional Theory. The experimentally observed shifts are well reproduced with a simple random model of the disorder, thus confirming the assignment of the resonances. The (31)P chemical shifts are very sensitive to changes in the lattice parameter and chemical surroundings. These effects nearly compensate and explain why the (31)P chemical shifts in pure InP and GaP are nearly identical whereas a large difference would be expected based on the observed shift difference for the P[In4] and P[Ga4] coordinations in In0.483Ga0.517P.

Section: Isolated Bhn (N = 0 To 3) Radicals On and At The Si(100) 3×1supporting

confidence: 75%

Section: Introductionmentioning

confidence: 99%

A multi-nuclear magnetic resonance and density functional theory investigation of epitaxially grown InGaP₂

Knijn

Bentum

Phys. Chem. Chem. Phys.

et al. 2016

“…To gain insight into the preparation processes and the structural and electronic properties of the boron-silicon heterojunction, we modeled the decomposition of B 2 H 6 molecules and the deposition of BH n (n = 1-4) molecular/radicals on a Si substrate at the early stages of the PureB processes [10,25,26], and a-B/c-Si interfaces [10,27]. Here we briefly review our recent theoretical work on the local structure, chemistry and electronic properties of a-B/c-Si interfaces.…”

Section: Boron-silicon Junction Formation Premise Based On Ab Initio Modelingmentioning

confidence: 99%

Mechanism of Electronegativity Heterojunction of Nanometer Amorphous-Boron on Crystalline Silicon: An Overview

Sberna

et al. 2021

Crystals

The discovery of the extremely shallow amorphous boron-crystalline silicon heterojunction occurred during the development of highly sensitive, hard and robust detectors for low-penetration-depth ionizing radiation, such as ultraviolet photons and low-energy electrons (below 1 keV). For many years it was believed that the junction created by the chemical vapor deposition of amorphous boron on n-type crystalline silicon was a shallow p-n junction, although experimental results could not provide evidence for such a conclusion. Only recently, quantum-mechanics based modelling revealed the unique nature and the formation mechanism of this new junction. Here, we review the initiation and the history of understanding the a-B/c-Si interface (henceforth called the “boron-silicon junction”), as well as its importance for the microelectronics industry, followed by the scientific perception of the new junctions. Future developments and possible research directions are also discussed.

“…First-principles approaches have been applied to investigate the geometries of pure Si surfaces [9,10,16], the Si surfaces with hydrogen-termination [10], B doping in Si [17][18][19], and B on the Si surfaces [19][20][21]. We investigated deposition of BH n (n = 0 to 3) radicals on the Si{0 0 1}2 × 1:H surface [22] which is stable at high temperature (~640 °C [15]). Here we further investigate the deposition of the BH n (n = 0 to 3) radicals on the Si{0 0 1}3 × 1:H surface which has high stability at low temperature [15].…”

Section: Introductionmentioning

confidence: 99%

Stability, geometry and electronic properties of BH_n (n = 0 to 3) radicals on the Si{0 0 1}3 × 1:H surface from first-principles

J. Phys.: Condens. Matter

Mohammodi

Nihtianov

et al. 2020

A new generation of radiation detectors relies on the crystalline Si and amorphous B (c-Si/a-B) junctions that are prepared through chemical vapor deposition of diborane (B2H6) on Si at low temperature (~400 °C). The Si wafer surface is dominated by the Si{0 0 1}3 × 1 domains that consist of two different Si species at low temperature. Here we investigate the geometry, stability and electronic properties of the hydrogen passivated Si{0 0 1}3 × 1 surfaces with deposited BH n (n = 0 to 3) radicals using parameter-free first-principles approaches. Ab initio molecular dynamics simulations using the density functional theory (DFT) including van der Waals interaction reveal that in the initial stage the BH3 molecules/radicals deposit on the Si(–H), forming (–Si)BH4 radicals which then decompose into (–Si)BH2 with release of H2 molecules. Structural optimizations provide strong local relaxation and reconstructions at the deposited Si surface. Electronic structure calculations reveal the formation of various defect states in the forbidden gap. This indicates limitations of the presently used rigid electron-counting and band-filling models. The attained information enhances our understanding of the initial stage of the PureB process and the electric properties of the products.