The effect of substrate temperature upon the compositions of Mg and Se in Zn_1‐xMg_x Se_y Te_1‐y layer grown by MOVPE

Abstract

The growth of Zn1‐xMgx Sey Te1‐y layers was performed on (100) ZnTe substrate by metalorganic vapour phase epitaxy using dimethylzinc, bis‐methylcyclopentadienyl‐magnesium, diethyltelluride and diethylselenide. The effects of substrate temperature upon the compositions of Mg and Se have been investigated. The Mg composition in Zn1‐xMgx Sey Te1‐y layer is significantly enhanced at low substrate temperature. Although the Se composition decreases with decreasing the substrate temperature, Zn1‐xMgx Sey Te1‐y layer with a relatively high Se composition of 0.3 is obtainable at a low substrate temperature as low as 380 ºC. For all the layers, a two‐mode behaviour with ZnTe‐ and MgTe‐like longitudinal optical phonon modes is confirmed by Raman scattering. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Compositions of Mg and Se, surface morphology, roughness and Raman property of Zn1−Mg Se Te1− layers grown at various substrate temperatures or dopant transport rates by MOVPE

“…This tendency is roughly similar to those of ZnTe [11,12] and Zn 1À x Mg x Te [9] layers grown by MOVPE. According to data on XRD profile obtained previously [8] a (400) diffraction peak from Zn 1À x Mg x Se y Te 1À y layer is observed together with a (400) peak from ZnTe, independent of substrate temperature. By using the lattice constant estimated from the diffraction angle, the degrees of the lattice mismatch between the layer and ZnTe substrate are plotted in the same figure.…”

“…1 shows the substrate temperature dependencies of Mg and Se composition of undoped Zn 1 À x Mg x Se y Te 1 À y layers. Here, the data on P-doped Zn 1 À x Mg x Se y Te 1 À y layer obtained previously [8] is added in the same figure as a reference. The Mg and Se compositions for undoped Zn 1 À x Mg x Se y Te 1 À y layers show almost the same substrate temperature dependencies as for P-doped Zn 1 À x Mg x Se y Te 1 À y layer.…”

“…Undoped and P-doped Zn 1 À x Mg x Se y Te 1 À y layers have been grown by atmospheric pressure MOVPE in almost the same manner as employed in the previous studies [8,9]. Briefly, DMZn, (MeCp) 2 Mg, DETe and DESe were used as source materials while trisdimethylaminophosphorus (TDMAP) was used as a dopant source.…”

“…In our previous study [8], Zn 1À x Mg x Se y Te 1À y layers were successfully grown on (100) ZnTe substrates using dimethylzinc (DMZn), bis-methylcyclopentadienyl magnesium ((MeCp) 2 Mg), diethy;ltelluride (DETe) and diethylselenide (DESe). Through the study, Zn 1À x Mg x Se y Te 1À y layer with a relatively high Se composition of 0.3 was demonstrated on (100) ZnTe substrate at a substrate temperature as low as 380 1C [8]. As the investigation on growth of Zn 1À x Mg x Se y Te 1À y layer is still in its infancy, however, more studies on growth and characterization are needed.…”

“…So far, several investigations have been reported on the preparation of Zn 1À x Mg x Se y Te 1À y by means of molecular beam epitaxy [2,6,7]. Unfortunately there are only a few reports on the growth of Zn 1À x Mg x Se y Te 1À y using metalorganic vapor phase epitaxy (MOVPE) [8], which is a potential epitaxial growth technique for mass production. Also, there are few trials on the doping of Zn 1À x Mg x Se y Te 1À y using MOVPE.…”