Effects of wavelength upon photoluminescence properties of ZnTe layers grown by photo-assisted MOVPE

Effects of illumination wavelength upon the growth rate and photoluminescen ce properties of undoped and aluminum (Al)-doped ZnTe layers have been inve stigated under a Te-rich growth condition by xenon-lamp-assisted metalorgan ic vapor-phase epitaxy. Even illumination with wavelengths longer than 600 nm, which hardly enhance the growth rate, deteriorates the quality of undop ed and Al-doped ZnTe epilayers. Illumination with wavelengths, which enhanc e the growth rate, i.e., illumination by photons having energies higher tha n the band gap of ZnTe, ensures the appearance of strong free exciton emiss ion for undoped layers. This also brings about a strong donor-acceptor pair luminescence for Al-doped layers. (C) 2000 Elsevier Science B.V. All right s reserved.