Electron Structure and Mechanism of Excitation of the Rare-Earth ions in the III-V Semiconductors
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ELEAM"E SRrcin AND MECHNISM OF rXCITnTIO OF THE RARu-uARTH IONS IN THE III-V SmIIcxn vUTs VADIM F.HASTWV State Technical University, St. Petersburg, Russia
Experimental
Physics
Departaent,195251
ABSTRACT The review of results of EPR, ODLR, RBS and PL investigations of the IIIV semiconductors doped with rare-earth elements is represented. The possible sites of RE related centers in hostare discussed. The possible mechanism of excitation of intrashell f-f transitions is considered. The simple theoretical model of the substitutional RE center in a binary semiconductors is discussed.
INTRODUCTION There are two main reasons of an interest of researchers to semiconductors doped with rare-earth (RE) atom. The first, its electron structure is differenced from other impurities. The second, a possibility of preparing semiconductors having new magnetic and optical properties. In the last few years RE doped semiconductors have attracted much attention for their potential application to light emitting devices with
temperature stable wavelengths. These materials combine the advantages atom-like, intra-4f-shell transitions of RE-dopends with ability
of of
semiconductors to activate the emission by minority-carrier injection. Systematic investigations of semiconductors doped with rare-earth
elements had started over a decade ago. Over the next some years
several
technology methods were used for preparing these materials. At the same time an assortment of the experimental methods used for investigation of
the states
RE dopands in semiconductors
increased-
In
parallel with
traditional radio- and optical spectroscopy the Rutherford backscattering channeling and photo electron spectroscopy have started use at the last few
years. The nmber of investigating materials
have
increased also.
The
states of RE impurities are researching in solid solutions on base III-V compounds, in III-VI compounds among silicon and III-V's. In this work we consider an electron structure of some types of RE centers in semiconductors and a possible mechanism of activation of the f-f luainescence in binary III-V compounds according to an analyses experimental results and simple theoretical model of the RE center in these materials. In conclusion some ways of development of studies RE doped semiconductors are discussed.
CHARACTERISTIC OF THE TEIIOG OF SEICODUCT-ORS DOPED WITH RARE-MARfH ELWS Rare-earth-doped single crystal and epitaxtal films have been grown using all the technological methods: growth of dendritic GaP and InP crystals from nonstechiometric melts [1,2]; the Czochralski method in the case purity III-V'a (3]; synthesis and diffusion through the melt of GaAs and InP [4]; horizontal zone melting of GaAs and GaSb [5); molecular beam epitaxy III-V's and Si (6]; ion-implantation doping of III-V's and Si [7,8]; MOCVD [9,10] et al. The main difficulty in using rare-earth elements is their extremely high chemical activity. Consequently, serious problems are encountered in the preparation of ultra pure RE elements and their storage.
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