The Effects of Dual Acceptor (Na, N) Doping on Zn and O Sites in ZnO

ZnO is an attracted semiconducting material because of the intriguing structural, electronic and optical properties as well as the properties can easily be tuned for applications. However, p-type doping is an essential research interest to overcome the hindering of the applications of n-type ZnO for next-generation advanced electronic and optoelectronic devices. In this article, we focus on the p-type acceptor mono (Na, N) and dual (Na-N) doping effects on the structural, electronic and optical properties of ZnO using first-principles calculations based on the density functional theory (DFT). Detailed DFT analysis reveals that the structure of ZnO distorted resulting in (Na, N) and (Na-N) doping, respectively. Band structure calculation highlights the confirmation of p-type ZnO for both types of doping introduced by acceptor impurity bands at the top of the valence band and pushing the Fermi level into the valence band. The band gap of ZnO is increased for Na and Na-N doping, while decreases for N doping.  The widening of the band gap with Na and Na-N doping could be explained by Burstein Moss effect. In this study the band gap can be tuned in between 0.58 and 0.93 eV. Importantly, enhancement of the absorption and photoconductivity in the near band edge region attributed to (Na, N) and (Na-N) could be extended its applications in high-performance p-type based electronic and optoelectronic devices

On the Consistency of the Solutions of the Space Fractional Schr\"odinger Equation

Recently it was pointed out that the solutions found in literature for the space fractional Schr\"odinger equation in a piecewise manner are wrong, except the case with the delta potential. We reanalyze this problem and show that an exact and a proper treatment of the relevant integral proves otherwise. We also discuss effective potential approach and present a free particle solution for the space and time fractional Schr\"odinger equation in general coordinates in terms of Fox's H-functions

Voltammetric studies of some azo compounds derived from 4-methyl-6,7-dihydroxy coumarin in microemulsion and aqueous media

The cyclic voltammetric(CV) behavior of some azo compounds based on coumarin derivatives  was investigated in microemulsion systems and in aqueous solutions. The obtained results indicated that these compounds undergo an irreversible 4-electron reduction step leading to cleavage of the N=N center with the formation of amine compounds in all media. The effect of medium on the CV parameters was discussed. The total number of electrons involved in the reduction process was determined by controlled potential coulometry. Also, The effect of substituents on the electrode reaction pathway and the kinetic parameters of the electrode process were calculated and discussed. Based on the data obtained the electroreduction mechanism was suggested and discussed