Fabrication and Characterization of Silicon Quantum Dots by Sputtering Method

Abstract

Solar energy spectrum ranges from 0.5 eV to 3.5 eV. In the single junction solar cell, a single bandgap energy (e.g Eg=1.12 eV for Si) is converted to electron-hole pair (EHP) and which further helps in current conduction. The third-generation solar cell comes into picture when it is required to convert a range of solar energy spectrum into electric current with reduced cost. The third-generation PV solar cell is based on QDs. A semiconductor material will show quantum confinement effect when the Bohr's radius of that material is less than around 10 nm. The quantum confinement effect is used to tune the bandgap in QDSC. Control of physical parameters and morphology of thin film layer are essential for the synthesis of the quantum dots PV solar cell. Fabrication of the third generation photovoltaic (PV) solar cell uses thin film deposition technique to deposit dielectrics such as SiO2, Si3N4, SiC, and SiOx. The layer works as a barrier layer, passivation layer, capping layer, tunneling medium, and an intermediate (i)- layer in the p-i-n structure solar cell.
The presented work use radio frequency (RF) sputtering as deposition technique to fabricate the silicon rich oxide (SRO) and silicon dioxide (SiO2) layers on controlling the deposition parameters such as RF sputtering power, the proportion of sputtering gas flow rate, and sputtering deposition time. The fabricated device is examined for physical and optical properties using spectroscopic techniques such as a surface profiler, EDS-SEM, XRD, FTIR, UV-Vis, and PL.