skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Using MOVPE Growth to Generate Tomorrow's Solar Electricity


No abstract prepared.

; ; ;
Publication Date:
Research Org.:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org.:
OSTI Identifier:
DOE Contract Number:
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Crystal Growth; Journal Volume: 298; Journal Issue: 2007
Country of Publication:
United States

Citation Formats

Kurtz, S., Friedman, D., Geisz, J., and McMahon, W. Using MOVPE Growth to Generate Tomorrow's Solar Electricity. United States: N. p., 2007. Web. doi:10.1016/j.jcrysgro.2006.10.176.
Kurtz, S., Friedman, D., Geisz, J., & McMahon, W. Using MOVPE Growth to Generate Tomorrow's Solar Electricity. United States. doi:10.1016/j.jcrysgro.2006.10.176.
Kurtz, S., Friedman, D., Geisz, J., and McMahon, W. Mon . "Using MOVPE Growth to Generate Tomorrow's Solar Electricity". United States. doi:10.1016/j.jcrysgro.2006.10.176.
title = {Using MOVPE Growth to Generate Tomorrow's Solar Electricity},
author = {Kurtz, S. and Friedman, D. and Geisz, J. and McMahon, W.},
abstractNote = {No abstract prepared.},
doi = {10.1016/j.jcrysgro.2006.10.176},
journal = {Journal of Crystal Growth},
number = 2007,
volume = 298,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
  • We have recently reported high efficiencies in a monolithic III-V triple-junction solar cell design that is grown inverted with a metamorphic 1.0 eV bottom In{sub .27}Ga{sub .73}As junction. The biaxial stress and strain grown into this highly lattice-mismatched junction can be controlled by varying the design of a step-graded Ga{sub x}In{sub 1-x}P buffer layer, in which most, but not all, of the 1.9% misfit strain is relieved. A multi-beam optical stress sensor (MOSS) is a convenient tool for in situ measurement of stress during metal-organic vapor phase epitaxy (MOVPE) for the optimization of solar cell performance. The analysis of stressmore » from curvature data is complicated by significant temperature effects due to relatively small thermal gradients in our atmospheric-pressure MOVPE reactor. These temperature effects are discussed and approximations made to allow practical analysis of the data. The results show excellent performance of inverted In{sub .27}Ga{sub .73}. As solar cells grown with slight compressive stress, but degradation under tensile stress. The best devices had a V{sub oc} of 0.54 V and a dislocation density in the low 10{sup 6} cm{sup -2}. The in situ stress data is also compared with ex situ strain data derived from X-ray diffraction measurements.« less
  • The lack of a coherent national energy policy makes it difficult for the utilities to make the decisions about fuels and construction that are necessary, Mr. Crawford feels. He notes that a changeover to electricity is taking place in many industries, commercial establishments, environmental projects, transportation, and residential heating. With coal-fired power plants facing serious environmental restrictions, utilities will seek reasonable trade-offs between the environment, economy, and energy demand. Coal is expected to provide 40 percent of the generating capacity by the year 2000; nuclear fuel, 50 percent. Although nuclear bans were voted down at the polls in 1976, themore » utilities expect continued public concern over fuel reprocessing, waste disposal, and proliferation. Experience has shown that nuclear power plants operated in 1976 in a safe, clean, reliable, and economical manner. Electric power by alternate sources is not expected to make a significant contribution before the year 2000, and this should be taken into account when setting policies for other fuels. Conservation and the elimination of waste should underlie national policy and should be a joint effort of government and the private sector, according to Mr. Crawford. Even if a 20 percent energy savings is accomplished by 2000, electricity demand will still be four times the 1975 level. Incentives to attract the needed investment funds will mean legislation that improves rates of return and allows utilities to compete financially. (DCK)« less
  • In an effort to reproduce computationally the observed evolution of microstructurally small fatigue cracks (MSFCs), a method is presented for generating conformal, finite-element (FE), volume meshes from 3D measurements of MSFC propagation. The resulting volume meshes contain traction-free surfaces that conform to incrementally measured 3D crack shapes. Grain morphologies measured using near-field high-energy X-ray diffraction microscopy are also represented within the FE volume meshes. Proof-of-concept simulations are performed to demonstrate the utility of the mesh-generation method. The proof-of-concept simulations employ a crystal-plasticity constitutive model and are performed using the conformal FE meshes corresponding to successive crack-growth increments. Although the simulationsmore » for each crack increment are currently independent of one another, they need not be, and transfer of material-state information among successive crack-increment meshes is discussed. The mesh-generation method was developed using post-mortem measurements, yet it is general enough that it can be applied to in-situ measurements of 3D MSFC propagation.« less
  • The vapor pressures of the [beta]-diketonates Y(THD), Ba(THD), and Cu(THD), commonly used as precursors for MOVPE of YBa[sub 2]Cu[sub 3]O[sub 7], and Y(MCP) were measured at different temperatures. A time-resolved static method recording the pressure vs. time at constant temperature was used, permitting us to deduce the vapor pressure even if the materials tend to decompose. The values of the constants of the Clausius-Clapeyron equation log[sub 10]p(T)/p[sub 0] = A - B/T are A = 11.7, 8.7, 8.27, 16.6 and B = 4359, 2654, 3602, and 6453 K for Y(THD), Y(MCP), Ba(THD), and Cu(THD), respectively with p[sub 0] = 1more » Pa and temperature T in K. The thermal stability of the sources was measured and are discussed. 18 refs., 4 figs., 1 tab.« less
  • Fundamental aspects of MBE and MOVPE growth techniques are briefly discussed. The capabilities and limitation of the two epitaxial growth techniques are summarized. A few examples of the MOVPE and MBE growth of high crystalline quality semiconductor thin films are also given including the characterization results obtained from spectroscopic and high resolution x-ray diffraction methods.