Epitaxial growth and optical investigations of ZnTeO alloys

Abstract

We have grown zincblende-structured ZnTeO alloy semiconductors on GaAs substrates by molecular beam epitaxy using RF-excited O. O concentrations measured by secondary ion mass spectroscopy were found to increase with the increase of O 2 flow rate supplied during the growth, while the change of lattice constant measured by X-ray diffraction does not follow Vegard's law. It is considered that the O atoms are incorporated not only into group-VI sites but also as interstitials. Formation of other compounds such as ZnTeO 3 , Zn 2 Te 3 O 8 , and TeO 2 was not detected. Optical reflectance spectroscopy revealed the increase of the band-gap energy with O concentration that can be interpreted as the repulsive interaction between the energy states originated in the localized states of O and the conduction-band edge of host ZnTe.

Optical Characteristics of ZnTeO Thin Films Synthesized by Pulsed Laser Deposition and Molecular Beam Epitaxy

“…11 Experiments and calculations have suggested the presence of such an intermediate band in ZnTeO and the quaternary ZnMnTeO. 11 Bandgap reduction in ZnTe with the introduction of oxygen has also been reported by other research groups recently, 12,13 providing further evidence of an intermediate band in this alloy. In this work, the synthesis of ZnTeO thin films by pulsed laser deposition and molecular beam epitaxy is investigated to further examine the possible formation of an intermediate band or alloy system spanning the visible/ultraviolet (UV) spectral region.…”

Mutually beneficial doping of tellurium and nitrogen in ZnO films grown by metal-organic chemical vapor deposition

“…1(a). 14,22 It is interesting to note that the NH 3 addition causes the diffraction peak to be weaker and broader, indicating its suppression effect on the formation of the ZnTe crystallite. Moreover, a small peak located at 2h ¼ 25.4 can be seen for all the asgrown samples, which cannot be assigned to any of the ZnO related diffraction patterns but is consistent with the (111) orientated ZnTe of the zinc blende structure.…”

Intermediate-band solar cells based on dilute alloys and quantum dots

“…The methods for synthesizing ZnTe 1 -x O x alloy or oxygen isoelectronic centers in ZnTe are very diverse, which include crystallizing ZnTe powder at high temperature with adding oxygen [16] or ZnO [19], pulsed-laser deposition (PLD) [20], ion-implantation with pulsed laser melting [18], molecular beam epitaxy (MBE) [20,21], and so on. When oxygen atoms are introduced into ZnTe crystal, only O Te states around 0.4 eV below the CB edge are confirmed to be radiative, and therefore suitable for operating IB conversion [22,23].…”