skip to main content

Title: Fabrication and characterization of Al{sub 2}O{sub 3} /Si composite nanodome structures for high efficiency crystalline Si thin film solar cells

We report on our fabrication and characterization of Al{sub 2}O{sub 3}/Si composite nanodome (CND) structures, which is composed of Si nanodome structures with a conformal cladding Al{sub 2}O{sub 3} layer to evaluate its optical and electrical performance when it is applied to thin film solar cells. It has been observed that by application of Al{sub 2}O{sub 3}thin film coating using atomic layer deposition (ALD) to the Si nanodome structures, both optical and electrical performances are greatly improved. The reflectivity of less than 3% over the wavelength range of from 200 nm to 2000 nm at an incident angle from 0° to 45° is achieved when the Al{sub 2}O{sub 3} film is 90 nm thick. The ultimate efficiency of around 27% is obtained on the CND textured 2 μm-thick Si solar cells, which is compared to the efficiency of around 25.75% and 15% for the 2 μm-thick Si nanodome surface-decorated and planar samples respectively. Electrical characterization was made by using CND-decorated MOS devices to measure device’s leakage current and capacitance dispersion. It is found the electrical performance is sensitive to the thickness of the Al{sub 2}O{sub 3} film, and the performance is remarkably improved when the dielectric layer thickness is 90more » nm thick. The leakage current, which is less than 4x10{sup −9} A/cm{sup 2} over voltage range of from -3 V to 3 V, is reduced by several orders of magnitude. C-V measurements also shows as small as 0.3% of variation in the capacitance over the frequency range from 10 kHz to 500 kHz, which is a strong indication of surface states being fully passivated. TEM examination of CND-decorated samples also reveals the occurrence of SiO{sub x} layer formed between the interface of Si and the Al{sub 2}O{sub 3} film, which is thin enough that ensures the presence of field-effect passivation, From our theoretical and experimental study, we believe Al{sub 2}O{sub 3} coated CND structures is a truly viable approach to achieving higher device efficiency.« less
Authors:
 [1] ;  [2] ; ; ; ;  [1] ; ; ;  [3] ; ;  [4] ;  [5]
  1. Key lab of nanodevices and applications, Chinese Academy of Sciences, Division of nano-devices and related materials, Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Suzhou, 215123 (China)
  2. (China)
  3. Platform for Characterization & Test, Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Suzhou, 215123 (China)
  4. Oxford Instruments Plasma Technology, Yatton, Bristol, BS49 4AP (United Kingdom)
  5. School of Nano-Science and Nano-Engineering, Xi’an Jiaotong University, Suzhou, 215123 (China)
Publication Date:
OSTI Identifier:
22492238
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Advances; Journal Volume: 5; Journal Issue: 12; Other Information: (c) 2015 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ALUMINIUM OXIDES; CAPACITANCE; CLADDING; COMPARATIVE EVALUATIONS; COMPOSITE MATERIALS; DIELECTRIC MATERIALS; ELECTRIC POTENTIAL; FABRICATION; INTERFACES; KHZ RANGE; LAYERS; LEAKAGE CURRENT; PASSIVATION; REFLECTIVITY; SILICON; SILICON OXIDES; SOLAR CELLS; TEXTURE; THIN FILMS; TRANSMISSION ELECTRON MICROSCOPY