X-ray Diffraction and Raman Spectroscopy Analyses of GaSb-enriched Si Surface Formed by Applying Diffusion Doping Technique

Abstract

The paper studies the properties of surface and near-surface region of a single crystalline silicon sample doped with atoms of Ga (AIII) and Sb (BV). n-type single-crystal Si wafers were chosen as substrates, and samples were size of 8×10×0.5 mm3. For diffusion into silicon, Ga and Sb impurities were used with a purity of 99.999 and 99.998, respectively. The authors propose that a new heterostructure might form in the near-surface region of silicon that could be engineered by applying a relatively cheap diffusion method. The experimental and analysis results show that the composition and absorption spectrum of silicon start manifest certain changes, and can be used in the future as a functional material for solar cells. The result showed that randomly located islands with an average diameter of 1–15 μm are formed on the substrate surface. X-ray diffraction analysis was carried out using a Rigaku diffractometer to study the crystallographic parameters of islands formed with the participation of Ga and Sb atoms on the silicon surface. The energy spectrum was studied on Nanofinder High End Raman spectrometer (LOTIS TII) in order to determine the presence of complexes of Ga and Sb atoms within islands formed as a result of diffusion. The optical emission spectra in the new structure were studied using a Lambda 950 spectrophotometer. The measurements were carried out at room temperature, i.e., at 300°K. Having studied the results of X-ray analysis, Raman spectroscopy, and optical spectroscopy, the authors have revealed that Ga and Sb atoms form new Si0.44(GaSb)0.56 and Si0.75(GaSb)0.25-type binary compounds on Si surface.