Nearly Gaussian dependence between near-infrared photoluminescence and O/Si composition ratio of Si-rich SiO(x) film with buried Si nanocrystals.
O/Si composition ratio optimized near-infrared (NIR) photoluminescence (PL) from Si nanocrystal (nc-Si) precipitated in Si-rich SiO(x) grown by Ar-diluted SiH4 and N2O is demonstrated. By detuning N2O fluence and N2O/SiH4 ratio to adjust the O/Si composition ratio of SiO(x) from 1.38 to 0.88, a nonlinearly Gaussian-like dependency of PL versus O/Si ratio with its maximum at O/Si of 1.24 is obtained. Maximized Si atomic density of 44.64 atom.% and nc-Si related PL of 25 count/nm is observed from SiO(x) with O/Si = 1.24 grown at N2O fluence of 50 sccm and N2O/SiH4 flowing ratio as low as 5.5. The FTIR analysis clearly indicates that the strong absorption bands at 870 and 2250 cm(-1) contributed by Si-H bonds suggests the hydrogen-passivated nc-Si could efficiently preserve the NIR PL response. Further reduction on O/Si composition ratio inevitably transfers the phase of host matrix from Si2O3 to SiO, which exhausts residual Si atoms and greatly decreases nc-Si density to degrade the PL response.
Lin
Gong-Ru
GR
Graduate Institute of Electro-Optical Engineering and Department of Electrical Engineering, National Taiwan University, Taipei 106, Taiwan, RO China.
Chang
Chung-Hsiang
CH
Pai
Yi-Hao
YH