Improvement in the photocurrent collection due to enhanced absorption of light by synthesizing staggered layers of silver nanoclusters in silicon

Abstract

Abstract:The quest for increased efficiency of solar cells has driven the research in synthesizing photovoltaic cells involving Si based materials. The efficiency of solar cells involving crystalline Si is stalled around 25% for the last decade. Recently Shi et al. had shown that light trapping can be enhanced by fabricating double layers of Ag nanoparticles in silicon based materials. The light trapping is critically important in a photo devices such as solar cells in order to increase light absorption and efficiency. In the present work, we report enhancement in the absorption of light in Ag ion implanted Si substrates. Multiple low energies Ag ions, ranging from ~80 keV to ~30 keV, with different fluences ranging from ~1×1016 to ~1×10 17 atoms/cm 2 were sequentially implanted into commercially available Si (100) substrates followed by post-thermal annealing to create different sizes of Ag nanoclusters (NC) at different depths in the top 100 nm of the Si. The absorbance of light is increased in Ag implanted Si with a significant increase in the current collection in I-V (current-voltage) photo switching measurements. The experimental photovoltaic cells fabricated with the Agimplanted Si samples were optically characterized under AM (air mass) 1.5 solar radiation conditions (~1.0 kW/m 2 ). An enhancement in the charge collection were measured in the annealed samples, where prominent Ag NCs were formed in the Si matrix compared to the as-implanted samples with amorphous layers. We believe the enhancement of the photocurrent density from the samples with Ag NC is due to the improvement of efficiency of charge collection of e --h + pairs produced by the incident light.

Формирование композиционного материала на основе GeSi с наночастицами Ag методом ионной имплантации

“…Известно, что проявление плазмонного резонанса в наночастицах Ag сопровождается появлением в спек-трах отражения соответствующих данным резонансам селективных полос [11,14]. Подобные селективные поло-сы отражения наблюдались для ионно-синтезированных наночастиц Ag в стеклах в видимой области спектра [34] и в Si в ближнем ИК диапазоне [35]. Наличие таких резо-нансных полос в Si предсказывается различными расче-тами спектров экстинкции и поглощения, проведенных для системы, состоящей из матрицы Si с помещенной в нее наночастицей Ag размером 10−20 nm [12,34,36].…”

Study of thermal recrystallisation in Si implanted by 0.4‐MeV heavy ions

“…A silicon‐on‐insulator (SOI) material developed in microelectronics and space technologies because of its advantages compared to silicon bulk substrates . The SOI is a significant material for future low‐cost photonic integrated circuits because of its specific optical and electronic properties, which thanks to a very thin single layer on an amorphous backing, is a very suitable structure for ion channelling phenomena investigation …”

“…7,8 The SOI is a significant material for future low-cost photonic integrated circuits because of its specific optical and electronic properties, which thanks to a very thin single layer on an amorphous backing, is a very suitable structure for ion channelling phenomena investigation. 9,10 Implantation of the metallic ions into the volume of a semiconductor brings more efficient light absorption and electron injection into the Si matrix. 11 Ion implantation modifies the Si crystalline structure mainly in case of noble metals.…”

Фотоэлектрические свойства композитных слоев Si с наночастицами Ag, полученных ионной имплантацией и лазерным отжигом

“…Такая термическая обработка ведет к устранению структурных дефектов облучаемой матрицы, созданных имплантацией, а также стимулирует образование металлических НЧ. Ранее формирование НЧ Ag в Si проводилось методом ионной имплантации [7], в том числе с последующим термическим отжигом при T > 400 • C [8][9][10]. Однако было установлено, что такой отжиг приводит к потере примеси Ag из тонкого имплантированного слоя в результате его испарения или диффузии вглубь кристалла [8,10].…”