Optoelectronic and Birefringence Properties of Weakly Mg Doped ZnO Thin lms Prepared By Spray Pyrolysis.

Abstract

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.