Control of the arrangement of native vacancies and optical in III-VI compound semiconductors

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We have investigated the structural and optical propetries of Ga_2Se_3 films on (100) GaP and (100) GaAs substrates prepared by molecular beamepitaxy (MBE), and obtained following results ;The electron diffraction studies and Raman studies revealed that the superstructure was predominantly formed in the [011] direction by the sponataneous of native gallium vacancies in the defect zincblende structure under the seleniumdirection by the spontaneous ordering of native gallium vacancies in the defect zincblende structre under the seleniumrich conditionVery large absorption anisotropy (a>10^4cm^<-1>) was observed in the vacaucy-ordered Ga_2Se_3 at the wavelength of around 525nm. The absorption coefficient in [011] polarization is larger than that in [011] in a range of 480 to 580nm. Therefore, the vacancy-ordered Ga_2Se_3 behaves like a polarizer in the selected wavelength wavelength range. On the contrary, the optical absorption in the disordered Ga_2Se_3 was isotropic, which suggests that … More the absorption anisotropy is attributed to the vacancy orderingFrom the polarization dependence of the reflection spectra, it was found that the reflective index in [011] polarization is larger than that for [011] in the vacaucy-ordered Ga_2Se_3In the photoluminescence (PL) measurement at low temperature, a broad emission peak centered at around 610nm was observed in the vacaucy-ordered Ga_2Se_3. Furthermore, the intensity of the [011] polarization component was much stronger than that of [011] polarization in the vacancy-ordered Ga_2Se_3. This result indicates that the electron transition probability for [011] polarization is larger than that for [011] polarization in vacancy-ordered Ga_2Se_3, and corresponds to the large absorption coefficient for [011] polarization. On the other hand, in the disordered Ga_2Se_3, PL intensity was extremely weak, and deep level emissions centered at around 750 and 900nm were dominantFrom these results, we consider that the vacaucy-ordered Ga_2Se_3 has great potential as a new material for optoelectronic devices Less