Influence of H2O2 concentration on the structural and photoluminescent properties of porous silicon nanowires fabricated by metal-assisted chemical etching

Investigating the Ag-assisted Chemical Etching Kinetics in Growing Si-NWs and Fabricating the p-i-n core–shell Heterojunction Si-NW Array Solar Cells

“…The NW surface appears slightly rough at the edges; however, no signature of any porosity is evident. Usually, Si-NWs prepared by 2-step MACE (as described in ref ) possess lots of porosity on the surface, generated due to H 2 O 2 as the oxidizing agent at the second step of etching. Whereas in the one-step MACE technique adopted in the current work, even after 180 min of chemical etching, the Si-NWs possess a relatively smooth surface morphology, favorable for both the junction formation in core–shell multilayer NW-based solar cells and their photovoltaic performances.…”

“…Subsequently, an HF solution with H 2 O 2 as an oxidizing agent is used to etch the metal-deposited Si surface . Significant work has already been pursued on this 2-step etching process. − There is a less popular variant of MACE, where the deposition of metal catalysts and the etching of Si happen simultaneously within a single step. , However, this 1-step MACE involves some complex electrochemistry, which has not yet been fully explored. Such issues concern, for example, the detailed role of Ag + ions during different phases of their interaction at the electrolyte/metal/Si interface via the formation of metallic Ag 0 deposits and how their subsequent self-assembled dendrite structures in a fine-mesh network control the supply of Ag + ions to the Ag/Si etching front and thereby maintain the selective etching of Si throughout the etching span.…”

Metal-Assisted Catalytic Etching (MACE) for Nanofabrication of Semiconductor Powders

“…In conventional MACE of wafers, all the oxidant is added at the beginning of the etch. The etch rate depends on the concentration of H 2 O 2 [ 48 , 64 ]. When injection is used to deliver the oxidant, a low steady-state concentration is maintained that is set by a number of factors including the volume of the solution, the concentrations of silicon and oxidant, and the injection rate.…”

“…This low reflectivity has been used to improve the efficiency of solar cells [ 47 ]. Ag-catalyzed MACE has also been used to produce photoluminescent hierarchical porous layers, for which the wavelength of photoluminescence (PL) was tuned in response to the concentration of H 2 O 2 used as an oxidant [ 48 ]. Photoluminescence of SiNWs was found to be sensitive to exposure to O 2 [ 49 ], and PL quenching of porous SiNWs was used to demonstrate a reversible O 2 sensor [ 50 ].…”

Синтез Массивов Наноструктурированных Пористых Кремниевых Стержней В Кремнии Электронного Типа Электропроводности С Кристаллографической Ориентацией (111)

“…Н2О 2 и HNO 3 являются более реакционноспособными соединениями и сильными окислителями, чем Н 2 О, и предполагалось, что процесс образования наноструктурированных стержней будет протекать интенсивнее для всех добавок, что поспособствует уменьшению времени анодирования для достижения аналогичной морфологии. Известно, что варьирование концентрации H 2 O 2 способно изменить (увеличить) скорость травления в глубину и изменить плотность наноструктурированных стержней [46,47]. В настоящей работе концентрация H 2 O 2 составила менее 1%, что, как оказалось, недостаточно для формирования вертикального массива НПКС.…”