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

Title: Regularities in the melting and crystallization of CdTe-Al alloys

Authors:
; ; ; ; ; ;
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA), Office of Nonproliferation and Verification Research and Development (NA-22)
OSTI Identifier:
1244210
Report Number(s):
BNL-111859-2016-CP
R&D Project: 20062; NN200100
DOE Contract Number:
SC00112704
Resource Type:
Conference
Resource Relation:
Conference: SPIE Optics and Photonics 2016; San Diego, CA; 20160828 through 20160901
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; CdTe-Al; differential thermal analyses; isothermal holding; superheating; clusters

Citation Formats

Kanak A., Bolotnikov A., Kopach, O, Fochuk, P, Shcherbak, L, Nakonechnyi, I, and James, R.B. Regularities in the melting and crystallization of CdTe-Al alloys. United States: N. p., 2016. Web.
Kanak A., Bolotnikov A., Kopach, O, Fochuk, P, Shcherbak, L, Nakonechnyi, I, & James, R.B. Regularities in the melting and crystallization of CdTe-Al alloys. United States.
Kanak A., Bolotnikov A., Kopach, O, Fochuk, P, Shcherbak, L, Nakonechnyi, I, and James, R.B. 2016. "Regularities in the melting and crystallization of CdTe-Al alloys". United States. doi:. https://www.osti.gov/servlets/purl/1244210.
@article{osti_1244210,
title = {Regularities in the melting and crystallization of CdTe-Al alloys},
author = {Kanak A. and Bolotnikov A. and Kopach, O and Fochuk, P and Shcherbak, L and Nakonechnyi, I and James, R.B.},
abstractNote = {},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2016,
month = 8
}

Conference:
Other availability
Please see Document Availability for additional information on obtaining the full-text document. Library patrons may search WorldCat to identify libraries that hold this conference proceeding.

Save / Share:
  • We fabricated epitaxial CdTe:In/CdTe:As homojunction and CdZnTe/CdTe and CdMgTe/CdTe heterojunction devices grown on bulk CdTe substrates in order to study the fundamental device physics of CdTe solar cells. Selection of emitter-layer alloys was based on passivation studies using double heterostructures as well as band alignment. Initial results show significant device integration challenges, including low dopant activation, high resistivity substrates and the development of low-resistance contacts. To date, the highest open-circuit voltage is 715 mV in a CdZnTe/CdTe heterojunction following anneal, while the highest fill factor of 52% was attained in an annealed CdTe homojunction. In general, all currentvoltage measurements showmore » high series resistance, capacitancevoltages measurements show variable doping, and quantum efficiency measurements show low collection. Ongoing work includes overcoming the high resistance in these devices and addressing other possible device limitations such as non-optimum junction depth, interface recombination, and reduced bulk lifetime due to structural defects.« less
  • Crystallization and melting processes are analyzed for polypropylenes having broad or narrow molecular weight distribution and heterogeneous or homogeneous defect composition. The difference in melting temperatures, after rapid crystallization conditions, is related to the difference in chain structure and defects composition while after prolonged crystallizations at very high temperatures the high T{sub m} peak approaches the same value ({approx} 185{degrees}C) for both type of polypropylenes. Only the longest pure isotactic sequences crystallize at this temperature. No {beta} phase is formed when crystallizing from the isotropic melt any of the polypropylenes studied. The {gamma} phase appears as a consequence of themore » presence of defects in the chain and is favored at the high crystallization temperatures. The origin of the double endotherm from isothermally formed crystals is independent of the formation of either {alpha} or {gamma} crystals and it is interpreted as the result of a copolymeric sequence selection during the crystallization process.« less
  • The crystallization and melting of binary mixtures of linear polyethylene with either random ethylene copolymers (short-chain branched) or long-chain branched polyethylenes, have been investigated. Initially, model systems involving a linear polyethylene, with either hydrogenated poly(butadiene) or a three armed star hydrogenated poly(butadiene) were studied. Each of these components was a molecular weight faction with a narrow composition distribution. Molecular weights were matched for each pair so that the results and interpretations are not encumbered by polydispersity and fractionation effects. Kinetics and fusion subsequent to isothermal crystallization, without cooling, were studied. The necessary conditions of composition and crystallization temperature for themore » co-crystallization of the two components to occur was established. Based on these studies, polydisperse systems were investigated and the results will be reported.« less
  • The thermodynamics, kinetics, and computer simulations of crystallization and melting is discussed. The thermodynamics is shown to be well understood, although for many specific crystals not enough details for full description are available. Experiments on the crystallization kinetics of poly(ethylene) and poly(oxyethylene) in the presence of crystal nuclei as a function of molecular mass revealed that with increasing mass, the crystallization behavior deviates increasingly from that of small, rigid molecules. Instead of showing a continuously changing, linear crystallization rate with temperature through the equilibrium melting temperature, T{sub m}{sup 0}, these flexible macromolecules show a region of practically zero crystallization ratemore » between T{sub m}{sup 0} and about (T{sub m}{sup 0} - 15) K, creating a temperature region of metastability in the melt that cannot be broken by nucleation with pregrown crystals. Molecular Nucleation was proposed as a cooperative process to be of overriding importance for the description of polymer crystallization, and to be at the center of segregation of molecules of lower molecular mass by growing crystal fronts. Initial efforts to model sufficiently large crystals using Monte Carlo and molecular dynamics methods are presented. Some of the short-time intermediates in the melting, crystallization, and annealing processes seem to have little similarity to commonly assumed models of crystallization and melting and are presented as discussion topics.« less
  • The thermodynamics, kinetics, and computer simulations of crystallization and melting is discussed. The thermodynamics is shown to be well understood, although for many specific crystals not enough details for full description are available. Experiments on the crystallization kinetics of poly(ethylene) and poly(oxyethylene) in the presence of crystal nuclei as a function of molecular mass revealed that with increasing mass, the crystallization behavior deviates increasingly from that of small, rigid molecules. Instead of showing a continuously changing, linear crystallization rate with temperature through the equilibrium melting temperature, T{sub m}{sup 0}, these flexible macromolecules show a region of practically zero crystallization ratemore » between T{sub m}{sup 0} and about (T{sub m}{sup 0} - 15) K, creating a temperature region of metastability in the melt that cannot be broken by nucleation with pregrown crystals. Molecular Nucleation was proposed as a cooperative process to be of overriding importance for the description of polymer crystallization, and to be at the center of segregation of molecules of lower molecular mass by growing crystal fronts. Initial efforts to model sufficiently large crystals using Monte Carlo and molecular dynamics methods are presented. Some of the short-time intermediates in the melting, crystallization, and annealing processes seem to have little similarity to commonly assumed models of crystallization and melting and are presented as discussion topics.« less