Frequency-Dependent Sonochemical Processing of Silicon Surfaces in Tetrahydrofuran Studied by Surface Photovoltage Transients.

Artem Podolian,Viktor Schlosser,Oleg Korotchenkov,Andriy Nadtochiy

doi:10.3390/molecules26123756

Abstract

The field of chemical and physical transformations induced by ultrasonic waves has shown steady progress during the past decades. There is a solid core of established results and some topics that are not thoroughly developed. The effect of varying ultrasonic frequency is among the most beneficial issues that require advances. In this work, the effect of sonication of Si wafers in tetrahydrofuran on the photovoltage performance was studied, with the specific goal of studying the influence of the varying frequency. The applied ultrasonic transducer design approach enables the construction of the transducer operating at about 400 kHz with a sufficient sonochemical efficiency. The measurements of the surface photovoltage (SPV) transients were performed on p-type Cz-Si(111) wafers. Sonication was done in tetrahydrofuran, methanol, and in their 3:1 mixture. When using tetrahydrofuran, the enhanced SPV signal (up to ≈80%) was observed due to increasing sonication frequency to 400 kHz. In turn, the signal was decreased down to ≈75% of the initial value when the frequency is lowered to 28 kHz. The addition of methanol suppressed this significant difference. It was implied that different decay processes with hydrogen decomposed from tetrahydrofuran could be attempted to explain the mechanism behind the observed frequency-dependent behavior.

Highlights

IntroductionA growing body of research data shows that sonochemical synthesis of different materials, in nanophases, is useful and promising [3,4,5]
We sonicated tetrahydrofuran, which can act as a source of hydrogen capable of improving the photovoltaic response of Si wafers
The surface photovoltage (SPV) response was increased up to ≈80% due to sonication at 400 kHz, whereas the signal decreased down to ≈75% of the initial value when the frequency was lowered to about 28 kHz

Summary

Introduction

A growing body of research data shows that sonochemical synthesis of different materials, in nanophases, is useful and promising [3,4,5]. The sonochemical processing technique can provide a unique tool to modify the electronic properties following the response to the bubble collapse and breaking the chemical bonds on the surface in a variety of materials. This is helpful for the processing of silicon whose surface electronic properties can very intriguingly be influenced by the chemical preparation [16]

Methods

Results

Conclusion