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Semiconductor Physics, Quantum Electronics & Optoelectronics. 2014. V. 17, N 2. P. 155-159.
Nanostructures in lightly doped silicon carbide crystals
with polytypic defects 1Yeoju Institute of Technology (Yeoju University), Abstract. In this work, photoluminescence spectra of lightly doped SiC crystals with in- grown original defects are reported. Undoped SiC single crystals with the impurity concentration of ND - NA ~(2...8) x 1016cm-3 , N A ~ (2...8) x 1017cm-3 , and ND - NA ~ (1...5) x 1017cm-3 , ND ~ 1 x 1018cm-3 were investigated. The analysis of absorption, excitation and low temperature photoluminescence spectra suggests formation of a new micro-phase during the growth process and appearance of the deep-level (DL) spectra. The complex spectra of the crystals can be decomposed into the so-called DLi (i = 1, 2, 3, 4) spectra. The appearance of the DLi spectrum is associated with formation of new nano-phases. Data of photoluminescence, excitation and absorption spectra show the uniformity of different DLi spectra. Structurally, the general complexity of the DLi spectra correlated with the degree of disorder of the crystal and was connected with one- dimensional disorder, the same as in the case of the stacking fault (SFi) spectra. The DLi spectra differ from SFi spectra and have other principles of construction and behavior. The DLi spectra are placed on a broad donor-acceptor pairs emission band in crystals with higher concentrations of non-compensated impurities. The excitation spectra for the DL i and SF i spectra coincide and indicate formation of nanostructures 14H1⟨4334⟩, 10H2⟨55⟩, 14H2 ⟨77⟩, 8H⟨44⟩. Keywords: silicon carbide, polytype, stacking fault, photoluminescence spectra, nanostructure. Manuscript received 15.01.14; revised version received 29.04.14; accepted for publication 12.06.14; published online 30.06.14.
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