Growth of MgTe and Cd1−xMgxTe thin films by molecular beam epitaxy

Abstract

We report on the growth of the compound semiconductor MgTe as weil as the ternary alloy Cd l ~xMg,Tc by mokcular hcam cpitaxy. This is to our knowkdgc thc first time that this material has heen grown by any epitaxial technique. Bulk MgTe, which is hygroscopic, has a band gap of 3.0 eV and crystallizcs usually in thc wurtzite structure. Pseudomorphic films were grown on zincblende Cd Te suhstrates for a MgTe thickness helow a critical layer thickncss of approximately 500 nm. In addition, Cdl_,MgxTe epilayers were grown with a Mg conccntration hetween 0 and 68'1(, wh ich corresponds to a band gap betwcen 1.5 and 2.5 eV at room temperature. The crystalline quality of thc layers is comparabk to CdTc thin films as long as they are fully strained. The lauice constant of zincblende MgTe is slightly smaller than that of CdTe, and the lattice mismatch is as low as O.7'k. In addition highly n-type CdMgTe layers were fabricatcd by hromine doping. The tunability of the band gap as weil as the ralher good laUice match with CdTc makes the matcrial interesting for optoelectronic device applications for the entire visible range.

Structural Properties of Cd1-xMgxTe and Cd1-x-yMgxMnyTe Crystals

“…Our dependence of the lattice constant versus actual Mg content can be described by the following equation: α = 6.481 -0.071x. (1) The zinc blende lattice constant of MgTe was found to be 6.41 Α by extrapolation of the above equation, which is lower than that reported by Waag et al (6.435 Å) for MBE (molecular beam epitaxy) grown thin films [6]. As it is seen in Fig.…”

<i>Ab Initio</i> Study of MgSe Self-Interstitial (Mg<i>_i </i>and Se<i>_i</i>)

“…They are used in various commercial applications in electronics, visual displays high density optical memories, solid state laser devices, photo detectors [1,2]. MgSe crystallizes in the zinc-blende (ZB), wurzite (WZ) and rock-salt (RS) structures [3].…”

Doping of the Wide-Gap Semiconductor Cd1-xMgxTe During Molecular Beam Epitaxy

“…The ternary wide-gap semiconductor (CdMg)Te seems to be a promising candidate for optoelectronic devices for the whole visible range of light [1]. (CdMg)Te has been found to be suitable for optoelectronics, already demonStrated in 1967 by the fabrication of an electroluminescent diode [2], but the crystal growth and the purity of the base materials turned out to be critical [3].…”

“…(CdMg)Te has been found to be suitable for optoelectronics, already demonStrated in 1967 by the fabrication of an electroluminescent diode [2], but the crystal growth and the purity of the base materials turned out to be critical [3]. By the use of molecular beam epitaxy (MBE) (CdMg)Te has recently been produced aS high quality thin films on (CdZn)Te substrates [1]. The lattice mismatch between CdTe and zinc blende MgTe has been found to be as low as 1% at room temperature.…”