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Title: Physics of Solid-Phase Epitaxy of Hydrogenated Amorphous Silicon for Thin Film Si Photovoltaics

Authors:
; ; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
908194
DOE Contract Number:
AC36-99-GO10337
Resource Type:
Conference
Resource Relation:
Conference: Amorphous and Polycrystalline Thin-Film Silicon Science and Technology: Proceedings of the Materials Research Society Symposium, 18-21 April 2006, San Francisco, California; Materials Research Society Symposium Proceedings, Vol. 910; Related Information: Paper No. 0910-A15-05
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; 36 MATERIALS SCIENCE; EPITAXY; PHYSICS; SILICON; THIN FILMS; PHOTOVOLTAIC CELLS; Solar Energy - Photovoltaics; Silicon Materials and Devices

Citation Formats

Stradins, P., Yan, Y., Young, D. L., Teplin, C. W., Iwaniczko, E., Xu, Y., Jones, K., Teeter, G., Mahan, A. H., Branz, H. M., and Wang, Q.. Physics of Solid-Phase Epitaxy of Hydrogenated Amorphous Silicon for Thin Film Si Photovoltaics. United States: N. p., 2006. Web.
Stradins, P., Yan, Y., Young, D. L., Teplin, C. W., Iwaniczko, E., Xu, Y., Jones, K., Teeter, G., Mahan, A. H., Branz, H. M., & Wang, Q.. Physics of Solid-Phase Epitaxy of Hydrogenated Amorphous Silicon for Thin Film Si Photovoltaics. United States.
Stradins, P., Yan, Y., Young, D. L., Teplin, C. W., Iwaniczko, E., Xu, Y., Jones, K., Teeter, G., Mahan, A. H., Branz, H. M., and Wang, Q.. Sun . "Physics of Solid-Phase Epitaxy of Hydrogenated Amorphous Silicon for Thin Film Si Photovoltaics". United States. doi:.
@article{osti_908194,
title = {Physics of Solid-Phase Epitaxy of Hydrogenated Amorphous Silicon for Thin Film Si Photovoltaics},
author = {Stradins, P. and Yan, Y. and Young, D. L. and Teplin, C. W. and Iwaniczko, E. and Xu, Y. and Jones, K. and Teeter, G. and Mahan, A. H. and Branz, H. M. and Wang, Q.},
abstractNote = {},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 2006},
month = {Sun Jan 01 00:00:00 EST 2006}
}

Conference:
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  • The chemical interface structure between phosphorus-doped hydrogenated amorphous silicon and aluminum-doped zinc oxide thin films is investigated with soft x-ray emission spectroscopy (XES) before and after solid-phase crystallization (SPC) at 600C. In addition to the expected SPC-induced phase transition from amorphous to polycrystalline silicon, our XES data indicates a pronounced chemical interaction at the buried Si/ZnO interface. In particular, we find an SPC-enhanced formation of Si-O bonds and the accumulation of Zn in close proximity to the interface. For an assumed closed and homogeneous SiO2 interlayer, an effective thickness of (5+2)nm after SPC could be estimated.
  • Poly-crystalline silicon (poly-Si) thin films have been prepared by aluminum induced crystallization (AiC) technique. Hydrogenated amorphous silicon (a-Si:H) thin films were prepared by sputtering a silicon target in hydrogen and argon ambient. It was observed that deposition rates increased more than two folds with the introduction of the hydrogen in the deposition chamber. The a-Si:H thin films were coated with a thin layer of sputtered aluminum (AI). X-ray diffraction (XRD) confirmed that the crystallization commenced at as low as 225 C. The depth profile of the annealed samples, obtained by scanning Auger microscopy (SAM), did not show any layer exchangemore » below 300 C. The SAM analysis showed clear layer exchange in the higher temperature ( >350 C) region.« less
  • The authors demonstrate that the internal field of a thin a-Si:H pin solar cells can be measured using the transient-null-current method. This method was previously developed to measure the internal field profile in a-Si alloy Schottky barrier. The internal electric field profile was determined by measuring the forward-bias voltages that tune the transient photocurrents generated by a pulsed laser at various wavelengths to zero. They adopt the same technique to a-Si:H p-i-n solar cells. In the case of p-i-n structure, they need to consider both space charge contributed by photogenerated carriers and carrier recombination which disturb the internal field. Theymore » use two critical conditions to minimize these effects. (1) To limit the contribution of photocarriers to space-charge distribution, the total charge collected is less than 10{sup {minus}10} C per pulse, and a repetition rate 1 Hz is used to ensure that the diode remains close to its equilibrium state, (2) The measuring time window is about 1--6 {micro}s following the displacement current. Typically the RC constant of diode is <1 {micro}s and the rise time of the forward-bias recombination current is 6.0 x {micro}s. They apply the signal average to process the forward-bias voltage. The error is within {+-}0.05 V. With this technique they can study the effect of variety of structure design or processing on the device performance.« less
  • Hydrogenated silicon (Si:H) thin films were fabricated on glass substrates by low frequency inductively coupled plasma-assisted chemical vapor deposition using a silane precursor with low hydrogen dilution at room temperature. The crystallinity and microstructure properties of the Si:H thin films deposited at different inductive radio-frequency (rf) power density were systematically studied by Raman spectroscopy, x-ray diffraction, and scanning electron microscopy. We found that at a low rf power density of 16.7 to 20.8 mW/cm{sup 3}, the structure of silicon thin films evolves from a completely amorphous phase to an intermediate phase containing both amorphous and microcrystalline silicon. As the powermore » density is increased to a moderate value of 25 mW/cm{sup 3}, a highly crystallized (111)-preferred hydrogenated microcrystalline silicon ({mu}c-Si:H) film featuring a vertically aligned cone-shaped structure, is emerging. Both the crystallinity and deposition rate exhibit a monotonic increase with the increase in the rf power density, reaching a maximum value of 85% and 1.07 nm/s, respectively, at a power density of 41.7 mW/cm{sup 3}. Scanning electron microscopy reveals that continuous and dense {mu}c-Si:H films with grain size of tens to hundreds nanometers can be achieved deterministically without the formation of amorphous incubation layer, and this is of great importance for synthesis of multilayer structures in p-i-n solar cells. The formation mechanism of the {mu}c-Si:H films and the elimination of the amorphous incubation layer are explained in terms of the high electron density and the plasma-surface interactions.« less