Electron paramagnetic resonance techniques were used to investigate singly-ionized Se vacancy centers, VSe+, in epilayers which had been grown by means of molecular beam epitaxy. Both undoped and N-doped films were studied. Spectra which were obtained at 8K and 9.45GHz, as the magnetic field was rotated in the plane from [100] to [010], revealed an isotropic signal at g = 2.0027; with a line-width of 5.8G. The appearance of the electron paramagnetic resonance signal could be correlated with an increase in the Zn/Se beam equivalent pressure ratio during growth, in the case of undoped films, and with an increase in the N content in the case of doped films. It was concluded that the singly-ionized Se vacancy was the predominant point defect in many molecular beam epitaxially-grown ZnSe layers, and that these defects might play a role in compensation mechanisms in heavily N-doped ZnSe thin films.

S.D.Setzler, M.Moldovan, Z.Yu, T.H.Myers, N.C.Giles, L.E.Halliburton: Applied Physics Letters, 1997, 70[17], 2274-6