Optical Investigations of MgO Quantum Dots under Pressure Effect at Near-infrared Region

MgO quantum dots (MgO QDs) are prepared using chemical bath deposition technique. The prepared MgO QDs are characterized by UV-visible (UV-vis) spectrophotometry, Fourier Transformation-Infrared (FTIR) and X-ray diffraction (XRD). The crystallite size goes up as pressure increases and corresponding to transmittance. The structural properties of XRD are elaborated in terms of different pressures, these properties of MgO QDs at different pressures from 50 to 300mbar have been investigated. The crystallite size is varied from 4.3nm to 7.2nm to 12.5nm for 200mbar, 250mbar and 300mbar, respectively. The XRD peaks are displayed at 2θ=38.1º, 42.8º, 31.3º and 34.5º that correspond to (111), (002), (100) and (002) planes, respectively. Also, the optical investigations of UV-vis and FTIR are detailed to understand the behavior of MgO QDs for different pressures. The transmittance, 200-1,200nm is in terms of wavelength at different pressures; 50mbar, 100mbar, 150mbar, 200mbar, 250mbar and 300mbar, while the high transmittance for more than 80% is exhibited at 200-300mbar. To investigate bandgap, it depends on the transmittance. At 200mbar and 423K, the bandgap’s nature has direct inter-band transition. The estimated bandgap is 5.01eV. The bandgap variation is attributed to non-stoichiometry of deposited layer. The FTIR spectra for MgO QDs at different pressures; 50-300mbar are researched to recognize many absorption peaks at different lengths indicating to varied phenomena of un-oxide sized, C-O stretching mode or chemical bonding of Mg-O production.