scispace - formally typeset
Search or ask a question
Author

Yeng-Cheng Hu

Bio: Yeng-Cheng Hu is an academic researcher. The author has contributed to research in topics: Nitric acid & Substrate (electronics). The author has an hindex of 1, co-authored 1 publications receiving 9 citations.

Papers
More filters
Journal ArticleDOI
TL;DR: In this article, the oxide layer on the surface of a p-type silicon substrate was grown under various growth times and temperatures while under nitric acid treatment, and an efficiency improvement of absolute 2% was obtained using their laboratory fabrication process.
Abstract: In this study, we investigate the effect of nitric acid oxidation on p-type silicon solar cells. The oxide layer on the surface of a p-type silicon substrate was grown under various growth times and temperatures while under nitric acid treatment. After 30 min of growth at 23 °C, an efficiency improvement of absolute 2% was obtained using our laboratory fabrication process.

9 citations


Cited by
More filters
Patent
23 Apr 2011
TL;DR: In this article, a method and structure for obtaining ultra-low surface recombination velocities from highly efficient surface passivation in crystalline silicon substrate-based solar cells by utilizing a bi-layer passivation scheme which also works as an efficient ARC.
Abstract: The disclosed subject matter provides a method and structure for obtaining ultra-low surface recombination velocities from highly efficient surface passivation in crystalline silicon substrate- based solar cells by utilizing a bi-layer passivation scheme which also works as an efficient ARC. The bi-layer passivation consists of a first thin layer of wet chemical oxide or a thin hydrogenated amorphous silicon layer. A second layer of amorphous hydrogenated silicon nitride film is deposited on top of the wet chemical oxide or amorphous silicon film. This deposition is then followed by annealing to further enhance the surface passivation.

32 citations

Journal ArticleDOI
TL;DR: In this paper, a boron-inkjet printing method was used to create high efficiency n-type Si cells with a Voc of 644 mV, a Jsc of 38.6 mA/cm2, and a fill factor of 76.3%.
Abstract: Formation of a well-passivated boron emitter for mass production of low-cost and high-efficiency n-type silicon solar cells is a major challenge in the photovoltaic industry. In this letter, we report on a novel and commercially viable method, inkjet printing, to create boron emitters. Phosphorus diffusion was used on the rear to form a back-surface held in conjunction with chemically grown oxide/silicon nitride (SiNx) stack on the front and back for surface passivation. Finally, front and back screen-printed contacts were formed through the dielectric stacks to fabricate large-area (239 cm2) n-type cells. This technology resulted in 19.0%-efficient p+-n-n+ cells with a Voc of 644 mV, a Jsc of 38.6 mA/cm2, and a fill factor of 76.3%. This demonstrates for the hrst time the promise of boron-inkjet-printing technology for low-cost and high-performance n-type Si cells.

14 citations

Journal ArticleDOI
TL;DR: In this article, the root cause of variation in surface recombination for Si wafers after different cleaning processes and for different passivation layers was investigated using a combination of calibrated photoluminescence (PL) imaging and transmission electron microscopy (TEM).
Abstract: In this work, the root cause of variation in surface recombination for Si wafers after different cleaning processes and for different passivation layers is investigated using a combination of calibrated photoluminescence (PL) imaging and transmission electron microscopy (TEM). The use of a HF-last or oxide-last cleaning and/or conditioning process is shown to have a strong impact on surface recombination for SiNx passivated surfaces, but little impact for Al2O3/SiNx stacks. For a SiNx passivation layer, cross-sectional TEM imaging revealed the formation of a ≈1–2 nm SiOx interlayer resulting from a controlled oxidation during the last cleaning/conditioning step. The presence of the SiOx layer reduces the interface defect density (Dit,midgap) by an order of magnitude and dramatically increases the effective carrier lifetime. However, for Al2O3/SiNx passivated surfaces, TEM studies revealed that a SiOx layer is formed at the interface between the c-Si and AlOx even for cleaning processes ending with HF-last treatment due to which the cleaning sequence has minimal impact on the effective carrier lifetime.

12 citations

Journal ArticleDOI
TL;DR: In this paper, the influence of surface cleaning on the quality of surface passivation achievable for boron-doped emitters was investigated, including the use of different combinations of HCl, HF, HNO3, and ozonated deionized water (DIO3).
Abstract: The use of proper surface preparation and cleaning methods for Si wafers prior to the deposition of passivation layers is essential to minimize surface recombination and realize high efficiencies (> 20%) in crystalline Si photovoltaic cells. In this work, the influence of wafer cleaning on the quality of surface passivation achievable for boron-doped emitters was investigated, including the use of different combinations of HCl, HF, HNO3, and ozonated deionized water (DIO3). These different surface preparations and cleaning sequences were performed on undiffused and boron diffused n-type Cz Si wafers, followed by the deposition of either silicon nitride (SiNx) or an aluminum oxide film capped with SiNx (Al2O3/SiNx stack). Additionally, both planar and anisotropically textured wafers were used. Injection-level dependent photoconductance measurements and calibrated photoluminescence imaging were performed on symmetrical boron diffused samples based on the different cleaning processes and passivation materials described above. Additionally, non-contact corona-Kelvin measurements were used to extract the total charge and interface defect density at the Si surfaces. We found that cleaning variations strongly influence carrier lifetime for SiNx passivated Si, but the effect is less pronounced in the case of Al2O3/SiNx stacks. It was further observed that DIO3-last treatment resulted in higher lifetimes for the SiNx stacks. Overall, it emerged that the (DIO3 + HF + HCl → HF → DIO3) clean is a promising and potentially low cost cleaning sequence for the photovoltaics industry.

10 citations