Metalorganic vapor phase epitaxy of Zn_1-xFe_xSe films

Thin single-crystalline films of the diluted magnetic semiconductor (DMS) Zn_1-xFe_xSe (0 < x ≤ 0.22) have recently been grown by metalorganic vapor phase epitaxy (MOVPE) [1]. The films were deposited on GaAs(100) substrates in a vertical axisymmetric stagnation-flow reactor equipped with a specially designed split inlet to minimize pre-reactions between the group II and VI precursors. The precursors were (CH₃)₂Zn:N(C₂H₅)₃, Fe(CO)₅ and H₂Se diluted in H₂ carrier gas. The Zn_1-xFe_xSe films were grown at 393°C, 120 Torr and VI/II = 1.11. These conditions were found to yield very high quality ZnSe films. Film growth rates ranged from 3.54 μm/h for x = 0.22 to 4.11 μm/h for x = 0.09 and are significantly (up to an order of magnitude) higher than the typical rates obtained by molecular beam epitaxy (MBE). The epilayers were characterized by X-ray diffraction (XRD), Raman, reflectance, absorption, and X-ray photoelectron spectroscopies (XPS) and by scanning electron microscopy (SEM). It appears that MOVPE is a suitable technique for growing high quality epitaxial Zn_1-xFe_xSe films and is very attractive for efficient growth of thick (several microns) DMS films for Faraday magneto-optical applications.