Study on the structural, optical and electrical properties of N-doped Ga2O3 films synthesized by sol-gel method

Ga2O3 exhibits great potential for applications in solar-blind ultraviolet photo detector, high-power electronic devices and solid-state light-emitting due to its ultra-wide band gap and high Baliga figure of merit. Here, Ga2(NxO1-x)3 films with varied nitrogen contents were prepared by the sol-gel technique. XRD analysis reveals that nitrogen doping contributes for growth of greater crystalline and SEM-EDS measurements confirm that the monoclinic crystal structure of Ga2(NxO1-x)3 is maintained to doping level of 3.26wt%; FTIR information indicates that nitrogen prefers to substitute for the O1 and O2 site of Ga2O3; XPS offers evidence that nitrogen tends to occupy oxygen vacancies and generate more gallium vacancies; UV-VIS shows that impurity defects appear above valence band, and the absorption position undergoes a red shift with nitrogen above 1.32wt%; PL shows Ga2(NxO1-x)3 films can emit light of various colors under excitation at 325nm, and the acceptor level is at 1.63eV∼2eV above the valence band; The conductivity of Ga2(NxO1-x)3 films is changed from n-type to p-type when nitrogen-doping is 0.96 wt% and the I–V curve composed of Ga2(NxO1-x)3 and Ga2O3 shows PDCR = 43 under the 254nm light. Therefore, the development of nitrogen-doped β-Ga2O3 has potential opportunities for applications in photoelectric devices.