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  • 2000-2004  (3)
  • 2001  (3)
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  • 2000-2004  (3)
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  • 1
    Electronic Resource
    Electronic Resource
    Current transport at the p-InP|poly(pyrrole) interface (2001)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 90 (2001), S. 1001-1010 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The interface between the inorganic semiconductor p-type InP and the conjugated polymer poly(pyrrole) exhibits the electrical characteristics of a Schottky diode. Capacitance–voltage measurements yield an average barrier height of 0.62 ± 0.01 eV at temperature T =298 K. At the same temperature, the empirical quality factor, extracted from current–voltage measurements, is near unity. However, the current–voltage measurements show a deviation from thermionic emission theory as the temperature is reduced, as witnessed by the increase of the quality factor and the curvature in the Richardson plot. Such deviation is best explained by the barrier inhomogeneity model, in which the barrier becomes voltage dependent due to the interaction of a small low-barrier region with a higher surrounding potential, termed the "pinch-off" effect. Traditional current–voltage models, including image force lowering or an interfacial layer, cannot predict the temperature dependence of the current–voltage data, although thermionic field emission may facilitate current transport in the interfaces with a higher doped InP substrate. Furthermore, the probability of sufficiently energetic incident charge carriers crossing the interface, termed the transmission coefficient, is smaller than that observed in metal Schottky diodes.© 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1380220
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  • 2
    Electronic Resource
    Electronic Resource
    Calculation of transmission coefficients at nonideal semiconductor interfaces characterized by a spatial distribution of barrier heights (2001)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 115 (2001), S. 433-445 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The use of temperature-dependent current–voltage and capacitance–voltage measurements in the determination of transmission coefficients, which can be related to various other heterogeneous charge-transfer rate constants, is analyzed for semiconductor interfaces characterized by a spatial distribution of barrier heights. The level of error introduced by the unknowing neglect of heterogeneity is analyzed using a discrete parallel network of regions with potentially voltage and temperature dependent effective areas and potential barriers. In general, the unknowing neglect of heterogeneity results in an overestimation of the transmission coefficient calculated from barrier heights based on capacitance–voltage measurements and an underestimation when based on barrier heights from temperature dependent current–voltage measurements (Richardson plots). Of particular focus is the calculation of transmission coefficients at semiconductor interfaces that exhibit anomalous behavior, most notably ideality or quality factors greater than unity, due to small-scale, "pinched-off," barrier inhomogeneities characterized by voltage-dependent effective barriers. In general, the meanings of various empirical treatments of current–voltage data in light of a voltage-dependent barrier height distribution are clarified with a particular focus on the extraction of equilibrium exchange current densities and the meaning of Richardson plots. To be specific, the model of Tung for pinched-off barrier inhomogeneities is used to demonstrate that multiple orders-of-magnitude errors in the calculation of transmission coefficients are possible with systems exhibiting only mildly anomalous behavior (ideality factors less than 1.3) if heterogeneity is neglected. The conditions of applied bias, dopant density, and temperature where the error is minimized are discussed along with the criteria for the rigorous extraction of transmission coefficients. The greatest confidence in the transmission coefficients occurs when the ideality factor is unity and the capacitance–voltage barrier agrees with the Richardson plot barrier. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1375154
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  • 3
    Electronic Resource
    Electronic Resource
    Locally Advanced Breast Cancer: Is Surgery Necessary? (2001)
    Boston, MA, USA : Blackwell Science Inc
    The @breast journal 7 (2001), S. 0 
    Details
    ISSN: 1524-4741
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: A retrospective analysis of the treatment of locally advanced breast cancer (LABC) was undertaken at Stanford Medical Center to assess the outcome of patients who did not undergo surgical removal of their tumors. Between 1981 and 1998, 64 patients with locally advanced breast cancer were treated with induction chemotherapy, radiation with or without breast surgery, and additional chemotherapy. Sixty-two (97%) patients received cyclophosphamide, doxorubicin, and 5-fluorouracil (CAF) induction chemotherapy. Induction chemotherapy was followed by local radiotherapy in 59 (92%) patients. Based on the clinical response to chemotherapy and patient preference, 44 (69%) patients received no local breast surgery. Radiotherapy was followed by an additional, non-doxorubicin-containing chemotherapy in all patients. The mean age of patients was 49 years. Of the 65 locally advanced breast cancers in 64 patients, 26 (41%) were stage IIIA, 35 (55%) were stage IIIB, and 4 (6%) were stage IV (supraclavicular lymph nodes only). Response to induction chemotherapy was seen in 59 patients (92%), with 29 (45%) achieving a complete clinical response and 30 (47%) a partial clinical response. With a mean follow-up of 51 months (range 7–187 months), 43 patients (67.2%) have no evidence of recurrent disease. Eight (12.5%) have recurred locally, and 21 (32.8%) have recurred with distant metastasis. Actuarial 5-year survival is 75%, disease-free survival is 58%, and local control rate is 87.5%. These data indicate that the routine inclusion of breast surgery in a combined modality treatment program for LABC does not appear necessary for the majority of patients who experience a response to induction chemotherapy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1524-4741.2001.007002131.x
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