Study of GaN_xAs_(1-x) semiconducting films grown by laser pulsed deposition on crystalline and amorphous substrates

摘要

The search for semiconductors with band gap energies in the green-blue region of the visible spectra has stimulated the development of new ternaries in the Ⅱ-Ⅵ and Ⅲ-nitrides systems. In the GaN-side of the GaNAs ternary compound it is expected that the band gap energy could be adjusted for all the visible spectra by changing the N concentration in the compound. We report on the growth of the ternary compound semiconductor GaN_xAs_(1-x) thin films by using the laser ablation deposition technique in a reactive nitrogen gas atmosphere, on crystalline GaAs(100) and Si(001) substrates and also on Corning glass substrates. We have studied the optical properties of these GaN_xAs_(1-x) films by means of the photoacoustic (PA) and the low temperature photoluminescence (PL) spectroscopies. PL spectra for GaNAs samples showed a broad emission band peaked at around 2.50 eV, a weak broad emission band at about 3.05 eV, and a double-peaked structure located at energies corresponding to violet luminescence band; besides, a very weak emission could be measured at energies of about 1.65-1.68 eV. We interpret these results in terms of the presence of the ternary GaNAs phase and cubic and hexagonal GaN phases.