Band-gap energy and electron effective mass of polycrystalline Zn3N2

Zn3N2 polycrystalline films with n(+)-type conductivity have been grown by metalorganic chemical vapor deposition and rf-molecular beam epitaxy with carrier concentration in the range between 10(19) and similar to 10(20) cm(-3). Oxygen contamination without an intentional doping was found to be a cause of high electron concentration, leading to a larger band-gap energy due to Burstein-Moss shift. The significant blue shift of the optical band gap E-opt with increasing carrier concentration n(e) obeys the relation E-opt=1.06+1.30x10(-14)n(e)(2/3). This evaluation enables the conclusion that the actual band-gap energy of Zn3N2 is 1.06 eV. Electron effective mass m(*) for Zn3N2 has been deduced from Fourier transform infrared reflectivity measurements to be (0.29 +/- 0.05)m(o). (c) 2006 American Institute of Physics.