Publication detail

Near-field measurement of ZnS:Mn thin-film electroluminescent devices

GRMELA, L. KALA, J. TOMÁNEK, P.

Original Title

Near-field measurement of ZnS:Mn thin-film electroluminescent devices

Type

conference paper

Language

English

Original Abstract

Thin film electroluminescent devices (TFELD) of inorganic phosphors have become of great interest since they offer a possible means of achieving a high-resolution, light-weight, compact video display panel for computer terminals or TV screens. Current inorganic TFEL phosphors are composed of II-VI wide bandgap semiconductor hosts (ZnS, SrS) which provide hot carriers (>2 eV) which impact excite luminescent centers (Mn, Tb, Ce, Cu). Sufficient hot carrier generation requires high field strengths (>1 MV/cm) exceeding the breakdown field of the phosphor thin film. An AC-biased dielectric/phosphor/dielectric layered structure allows reliable high field operation by current-limiting the electrical breakdown of the phosphor layer [1]. From a device point of view, a hysteresis in the brightness vs. applied voltage response curve is the most important advantage of AC-TFEL devices for large-area applications. In spite of the fact that the brightness of a memory-type EL is, in general, lower than that of non-memory ones, their advantage lies in the possibility of operating on an arbitary number of pixels in the matrix addressing mode at the same brightness level as the one-pixel device. Thus, memory devices are potentially more suitable for large area display operation [2]. To contribute to the local investigations of memory-type ZnS:Mn electroluminescent devices characteristics, we have been interested in the local electro-optical phenomena near the surfaces at the distances much less than the radiation wavelength. Beside a purely fundamental interest this is connected to the vigorous development of the scanning near-field optical microscopy. By scanning a 100 um x 100 um ACTFEL radiative surface in optical near-field we have found a pronounced hysteresis effect in the brightness vs. pulse width (B-W) response curve for memory-type ACTFEL devices driven near the threshold voltage. Moreover, we have investigated the dependence of the B-W characteristics on the ambient temperature and on the film thickness of the ZnS:Mn layer. The variations of the response times with respect to these parameters were also studied. The results will be reported in the paper.

Keywords

ZnS:Mn thin film, near-field measurement, brightness, pulse width, ambient temperatue

Authors

GRMELA, L.; KALA, J.; TOMÁNEK, P.

Released

10. 9. 2006

Publisher

EPFL Lausanne

Location

Lausanne, Switzerland

Pages from

326

Pages to

328

Pages count

3

URL

http://www.nfo9.org

BibTex

@inproceedings{BUT19858,
  author="Lubomír {Grmela} and Jaroslav {Kala} and Pavel {Tománek}",
  title="Near-field measurement of ZnS:Mn thin-film electroluminescent devices",
  booktitle="Near-field optics, Nanophotonics and Related Techniques",
  year="2006",
  number="1",
  pages="326--328",
  publisher="EPFL Lausanne",
  address="Lausanne, Switzerland",
  url="http://www.nfo9.org"
}