Silicon Nanocrystals Embedded in Nanolayered Silicon Oxide for Crystalline Silicon Solar Cells

Abstract

This study describes the fabrication of silicon nanocrystals (Si NCs) in silicon oxide layers, which led to highperformance passivation and enhanced carrier transport in crystalline silicon (c-Si) solar cells. These Si NCs comprised nanocrystalline transport pathways in ultrathin dielectrics for reinforced passivating contact structures (NAnocrystalline Transport path in Ultrathin dielectrics for Reinforcing (NATURE) contacts). Si NCs were formed in silicon oxide layers by depositing hydrogenated amorphous silicon oxide (a-SiO x :H) with different oxygen concentrations, followed by postdeposition annealing (PDA). Based on microscopic images, the silicon oxide layer was maintained after PDA, and the Si NCs were formed in the silicon oxide matrix, leading to a relatively low recombination current (178.8 fA/cm 2 ) compared with simple a-SiO x :H layer structures. Furthermore, the contact resistivity for the NATURE contact was 13.1 mΩ•cm 2 , which was comparable to that of a single a-SiO x :H layer with a low oxygen concentration. The developed NATURE contact structure expands the design flexibility scope for various functional devices containing a passivation contact layer. It allows for the production of c-Si solar cells with passivating contacts using thicker dielectric layers for improved reliability and long-term stability.

Hydrogenation of silicon-nanocrystals-embedded silicon oxide passivating contacts

“…The working pressure was 0.188 Torr, a plasma source power density was 32.5 mW cm −2 , and the substrate temperature was 180 °C. The detailed deposition conditions for the NATURE contact are found eleswhere [21]. Annealing was then performed at 750 °C for 30 min in forming gas (3% H 2 in 97% Ar) using a lamp furnace (ADVANCE RIKO, MILA-5050).…”

“…We have developed the NATURE contact (NAnocrystalline Transport Path in Ultra-thin dielectrics for Reinforced passivation contact) that achieves both thick SiO x layer deposition and efficient carrier transport [21]. The NATURE contact is a new passivating contact in which conductive silicon nanocrystals (Si-NCs) are embedded in the SiO x layer and carriers are transported through these Si-NCs.…”

Double-Barrier Quantum-Well Structure: An Innovative Universal Approach for Passivation Contact for Heterojunction Solar Cells

“…It is essential to optimize the contact layer before its application to solar cells. Tsubata et al 31 reported that Si nanocrystals are already embedded in the SiO x layer and play a vital role in charge transport along the nanolayered SiO x . In this regard, we tailored the nanocrystal size, crystalline volume fraction, etc., by controlling the CO 2 flow rate during deposition.…”

Silicon Nanoparticles Wrapped in a Double-Layer Coating of Chitin-Derived Nitrogen-Doped Carbon Nanosheet and Pitch-Based Carbon Enabling Efficient Lithium Storage

“…Fossil fuels have been widely used as a primary energy source since the mid-19th century due to their direct or indirect energy conversion ability. However, concerns have been raised about their nonrenewable nature and detrimental impact on the environment. − As a result, there is a growing interest in exploring alternative green energy sources such as solar, wind, tidal, and biomass to meet the increasing energy demands. − Nonetheless, the intermittent instability and limited energy utilization of these energy sources have hindered their widespread implementation. Thus, the development of efficient energy storage and conversion devices is crucial to address this challenge. − Lithium-ion batteries (LIBs) have emerged as dominant energy storage devices in the market due to their recyclability and memoryless characteristics. − The performance of LIBs is primarily influenced by the properties of the anode and cathode materials.…”