Electronic structure and optical properties of CdO from bulk to nanosheet: DFT approach

• The electronic and optical properties of CdO nanosheet were investigated.
• Band structure and DOS confirm that CdO nanosheet is direct band gap semiconductor.
• The principal tensor components of, ɛ2(ω), ɛ1(ω), n(ω), I(ω) and R(ω) were investigated.
• The calculated uniaxial anisotropy and birefringence show high effectiveness of CdO nanosheet for SHG.
• CdO nanosheet elucidates high effectiveness for optoelectronic applications.

First principle calculations of CdO nanosheet were performed with the help of full potential linear augmented plane wave (FPLAPW) method within the generalized gradient approximation (GGA) as implemented in WIEN2k program. Electronic structure and optical properties of CdO nanosheet have been calculated and discussed in this work. The calculated band structure shows that the CdO nanosheet is direct band gap EgΓ-Γ semiconductor. The band gap value so obtained is 0.8 eV. The contribution of different bands was analyzed on the basis of total (TDOS) and partial density of state (PDOS). A number of optical parameters have been calculated and discussed in details. Static dielectric constants are found to be 2.1 and 1.5 for ε1xx(ω) and ε1zz(ω). The static refractive index n(0) value for nxx(ω) and nzz(ω  ) are found to be 1.439 and 0.113 respectively. In the high energy region the reflectivity is about 26%. The average value of dielectric constant ε2average(ω) for CdO-bulk and nanosheet shows the critical point at 2.3 eV and 3.4 eV respectively. Calculated static birefringence values for CdO (bulk) and CdO nanosheet are −0.04 and −0.31, respectively. Valence electron charge density plot show mixed ionic covalent character having 38.71% ionicity. Scissor correction has been done in order to get the optical gap equivalent to experimental band gap (3.4 eV). CdO nanosheet show high efficiency for linear and non linear optical devices.