The role of Be incorporation in the modulation of the N doping ZnO

Postannealed Structural Relaxation and Phase Evolution of Quaternary Alloy BeMgZnO

“…Due to the Be in host lattice, the binding energy in BeZnO was significantly enhanced to 263 meV, which is rather important to realize exciton lasers with a low threshold. Besides the bandgap modulation, Be x Zn 1– x O with low Be content was found to be helpful in reducing the acceptor ionization energy and improving the stability of p-type ZnO. , Even though Be x Zn 1– x O has achieved such progress, two unexpected shortcomings impede its further applications: (1) the crystal quality of Be x Zn 1– x O deteriorates rapidly as the Be content increases because of the large lattice mismatch (ZnO: a = 0.325 nm, c = 0.525 nm; BeO: a = 0.27 nm, c = 0.43 nm); (2) Be can easily occupy the interstitial position of the lattice due to the small Be 2+ radius. − Additionally, according to the thermal stability investigation, Be atoms were observed to be easily diffused out from the host lattice, and as a result, the BeO second phase will be generated. , Alternatively, quaternary alloy Be x Mg y Zn 1– x – y O was proposed to further modulate the bandgap of ZnO, because it may have the chance to overcome the difficulties occuring in ternary alloy Be x Zn 1– x O and Mg x Zn 1– x O. − Recently, quaternary alloy Be x Mg y Zn 1– x – y O with low Be content and high Mg content was prepared to obtain the largest bandgap (5.14 eV) in wurtzite structure II–VI alloys . Due to the strong Be–O chemical bond, a small amount of Be plays a crucial role to stabilize the quaternary system.…”

“…Besides the bandgap modulation, Be x Zn 1−x O with low Be content was found to be helpful in reducing the acceptor ionization energy and improving the stability of p-type ZnO. 21,22 Even though Be x Zn 1−x O has achieved such progress, two unexpected shortcomings impede its further applications: Be can easily occupy the interstitial position of the lattice due to the small Be 2+ radius. 23−25 Additionally, according to the thermal stability investigation, Be atoms were observed to be easily diffused out from the host lattice, and as a result, the BeO second phase will be generated.…”

Hydrogen sensing properties of the ZnO(0 0 0 1¯) surface enhanced by Be doping: A first principles study

“…On the other hand, Be atom has a high migration energy in ZnO of 2.9 eV which means that it is a thermally stable dopant [46]. The incorporation of Be in ZnO will enhance the solubility of nitrogen in this material and this will lead to the realization of high ptype quality [47].…”

Effect of thermal treatment on points defects of Al-N codoped ZnO films

“…Codoping is an alternative method that has been proposed, using acceptors and reactive donors simultaneously in order to achieve p-type ZnO [4]. In several studies were used elements such as P [5,6], In [7,8], Be [9], Ag [10] and Al [11][12][13][14][15][16][17][18][19] in addition to nitrogen atoms, in order to increase incorporation of N into the ZnO crystalline lattice. Other important factors that help to p-doping are the growth temperature and the post-annealing process.…”