Direct measurement of potentials in a reactive ion-plasma etching system

Devices for direct measurement of the plasma potential and floating potential in a gas dis-charge in a reactive ion-plasma etching system are presented. The action of the devices devel-oped for this purpose is based on the creation of a local magnetic field that allows purposeful-ly changing the conditions of ambipolar diffusion of charged particles. This makes it possible to contact the probe with the body of a positive plasma column without the appearance of a floating potential on it. The results of measuring the plasma potential by the proposed and al-ternative methods are compared

One-Step Fabrication of Inverted Pyramid Textured Silicon Wafers via Silver-Assisted Chemical Etching Combing with Synergism of Polyvinylpyrrolidone (PVP)

Inverted pyramid-texturing of silicon surface has been proven to have great application potential in silicon solar cells. In this paper, we utilized Ag-assisted chemical etching (Ag–ACE) technology combing with polyvinylpyrrolidone (PVP) to fabricate an inverted pyramid textured Si surface. We call it Ag@PVP–ACE. The effect of different experimental parameters on etching results was observed. We show that the microstructure of the Si surface exhibited two states as the concentration of NH4HF2 and PVP concentration changed: polishing and inverted pyramid texturing. Meanwhile, we found inverted pyramids easier to form at the high temperature and low H2O2 concentration of the etching system. Consequently, compared to inverted pyramid structures fabricated by nanostructure rebuilding (NSR) technology and Ag@PVP–ACE, we consider that Ag@PVP–ACE technology could become a viable strategy for fabricating inverted pyramid textured Si wafers in Si solar cells production.

Fabrication of highly uniform nanoprobe via the automated process for tip-enhanced Raman spectroscopy

In a tip-enhanced Raman spectroscopy (TERS) system, using a sharp nanotip that comprises a noble metal is critical to attaining high spatial resolution and highly enhanced Raman scattering. A strongly acidic solution is typically used to fabricate gold nanotips in a quick and reliable manner. However, using an acidic solution could corrode the etching system, thereby posing hazardous problems. Therefore, both the corrosion of the etching system and human error induced by the conventional method considerably decrease the quality and reproducibility of the tip. In this study, we significantly increased the reproducibility of tip fabrication by automating the electrochemical etching system. In addition, we optimized the etching conditions for an etchant that comprised a KCl solution to which ethanol was added to overcome the limitations of the acidic etchant. The automated etching system significantly increases the yield rate of tip-fabrication reproducibility from 65 to 95%. The standard deviation of the radius of curvature decreased to 7.3 nm with an average radius of curvature of 30 nm. Accordingly, the automated electrochemical etching system might improve the efficiency of TERS.