The SU-8 spin-coating on silicon nanowires formed by cryogenic dry etching

Arrays of vertically aligned silicon nanowires were fabricated by cryogenic dry etching. The post-processing technology was developed to full coating of arrays of NWs by SU-8 and release the top side of SiNWs. The Schottky diodes were fabricated on arrays of SiNWs with and without SU-8 by gold evaporation. The cryogenic dry etching leads to defect formation with Ea=0.28 eV and concentration lower 5⋅1012 cm−3 in near-surface area in silicon, and no defect are detected in bulk silicon. However, oxygen plasma treatment used to release top side of SiNWs leads to increase of its concentration by two order and formation of defect with Ea=0.39 eV, σ = 1⋅10−16 cm2 and a concentration of 5⋅1014 cm−3 in a bulk of SiNWs deeper than 1 μm.

Photoemission Spectra from the Extended Koopman’s Theorem, Revisited

The Extended Koopman’s Theorem (EKT) provides a straightforward way to compute charged excitations from any level of theory. In this work we make the link with the many-body effective energy theory (MEET) that we derived to calculate the spectral function, which is directly related to photoemission spectra. In particular, we show that at its lowest level of approximation the MEET removal and addition energies correspond to the so-called diagonal approximation of the EKT. Thanks to this link, the EKT and the MEET can benefit from mutual insight. In particular, one can readily extend the EKT to calculate the full spectral function, and choose a more optimal basis set for the MEET by solving the EKT secular equation. We illustrate these findings with the examples of the Hubbard dimer and bulk silicon.

Thermal Disproportionation for the Synthesis of Silicon Nanocrystals and Their Photoluminescent Properties

In the past decades, silicon nanocrystals have received vast attention and have been widely studied owing to not only their advantages including nontoxicity, high availability, and abundance but also their unique luminescent properties distinct from bulk silicon. Among the various synthetic methods of silicon nanocrystals, thermal disproportionation of silicon suboxides (often with H as another major composing element) bears the superiorities of unsophisticated equipment requirements, feasible processing conditions, and precise control of nanocrystals size and structure, which guarantee a bright industrial application prospect. In this paper, we summarize the recent progress of thermal disproportionation chemistry for the synthesis of silicon nanocrystals, with the focus on the effects of temperature, Si/O ratio, and the surface groups on the resulting silicon nanocrystals’ structure and their corresponding photoluminescent properties. Moreover, the paradigmatic application scenarios of the photoluminescent silicon nanocrystals synthesized via this method are showcased or envisioned.