MgxZn1−xO thin films were deposited on glass substrate with x varied between 0.01 and 0.05 by spray pyrolysis at a temperature of 450 °C. The structural investigation showed that all thin films had ZnO wurtzite structure with a preferred (002) orientation. The gap energy was calculated using Tauc’s plot and it decreased over the Mg content by 0.07 eV. The charge carriers’ density dropped by an order of 105 as Mg content increased whereas the resistivity and the mobility increased. SEM observations revealed a significant difference between undoped and doped thin films. A 632.8 nm laser source prism coupler revealed 2 optical modes for every thin film in each Transverse Electric and Transverse Magnetic mode, the birefringence of the Mg doped films was positive. Both ordinary and extraordinary refractive indexes were found to decrease as the Mg content increased. Great intention has been paid to the relation between the refractive, charge carriers density and the optical band gap.

Zinc Oxide (ZnO) is is a multipurpose semiconductor with many uses such as ultra-capacitor electrode [1], spintronic devices [2], multigas sensing [3–6], piezoelectric devices [7], ultra-violet LEDs [8], detectors [9] as well as waveguides [10–12]. In its thin film form, ZnO has a large adaptation to several deposition methods such as chemical vapor deposition [13], pulsed laser deposition [14], spray pyrolysis [15], dip-coating [16] and electrochemical deposition [17]. ZnO has very interesting characteristics for application in electronics and optoelectronics devices, especially its exciton binding energy of 60 meV at 300K, a wide direct band gap of 3.37 eV [18]. In addition to an ordinary and extraordinary refractive indexes of ne = 2.006 and no = 1.990 respectively [19]. To modify its electrical properties, ZnO was doped with Group III elements such as Al, Ga and In which acted as donor dopants to reinforce its n-type electrical nature and group V elements such as N, P, As and Sb which acted as acceptor dopants which changed ZnO to be a p-type semiconductor [20]. Controlling the refractive index of ZnO thin films was achieved by several ways including thermal annealing [21] and doping with In [22], Te, N [23] and Mg [24]. However, the e↵ect of dopants on the optical and electrical properties of ZnO is still not well understood.

MgxZn1−xO thin films were deposited on glass substrate with x varied between 0.01 and 0.05 by spray pyrolysis at a temperature of 450 °C. The structural investigation showed that all thin films had ZnO wurtzite structure with a preferred (002) orientation. The gap energy was calculated using Tauc’s plot and it decreased over the Mg content by 0.07 eV. The charge carriers’ density dropped by an order of 105 as Mg content increased whereas the resistivity and the mobility increased. SEM observations revealed a significant difference between undoped and doped thin films. A 632.8 nm laser source prism coupler revealed 2 optical modes for every thin film in each Transverse Electric and Transverse Magnetic mode, the birefringence of the Mg doped films was positive. Both ordinary and extraordinary refractive indexes were found to decrease as the Mg content increased. Great intention has been paid to the relation between the refractive, charge carriers density and the optical band gap.