Combinatorial growth of Mg_x Zn_1–xO epilayers by chemical vapor deposition

Abstract

It was our aim to explore the growth of Mgx Zn1–x O epilayers on ZnO substrates using CVD at substrate temperatures around 650 °C which is considerably lower than necessary for the MOCVD growth which requires substrate temperatures above 900 °C. Metallic precursors (Zn, Mg) were used together with NO2 as oxygen precursor. The Mg content was determined from the shift of longitudinal optical phonon line as a function of the Mg composition. The properties of the films were investigated by low temperature photoluminescence. Epitaxial Mgx Zn1–x O films with fixed Mg compositions required an individual adjustment of the Mg reservoir temperature. We, therefore, explored the possibility of a combinatorial growth i.e. achieving a Mg gradient within one sample. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Fundamentals of zinc oxide as a semiconductor

“…Lautenschlaeger et al [249] reported the growth of MgZnO epilayers on ZnO single-crystal substrates using chemical vapor deposition at relatively low temperatures of ∼650 • C, without using organometallic precursors. Instead, they used metallic precursors (Zn, Mg) along with NO 2 as an oxygen precursor.…”

“…Instead, they used metallic precursors (Zn, Mg) along with NO 2 as an oxygen precursor. Epitaxial films with fixed Mg concentrations were found to require an individual adjustment of the Mg reservoir temperature, allowing Lautenschlaeger et al to explore the possibility of achieving a Mg gradient within one sample in a combinatorial approach using chemical vapor deposition [249].…”

Novel Chalcopyrites for Advanced Photoelectrochemical Water Splitting

“…75 Combinatorial studies explored the composition spreads of MZO with different deposition methods, such as pulsed laser deposition 77,78 and chemical vapor deposition. 79 In a previous combinatorial study, we showed that the conduction band position could be tuned by 0.5 eV as Mg concentration changes from 4 to 12%, 80 suggesting that it might be a suitable contact to CuGa3Se5 absorber. Integration of MZO as contact material resulted in significant efficiency improvements of CdTe 81 and CIGS 82,83 65a).…”

Codesigning Alloy Compositions of CdSeyTe1−y Absorbers and MgxZn1−xO Contacts to Increase Solar Cell Efficiency

“…There are varying reports on the Mg x Zn 1Àx O band gap (4.0-4.2 eV) at maximum Mg composition (x ¼ 0.36-0.46) at which phase segregation occurs, as it depends on the deposition technique, deposition rate, and substrate temperature. [8,9] Mg x Zn 1Àx O has also been studied using different combinatorial methods, such as pulsed laser deposition, [10] chemical vapor deposition, [11] and sputtering, [12] where we demonstrated Mg x Zn 1Àx O conduction band tuning and integrated it with wide-bandgap CuGa 3 Se 5 absorber to increase V OC close to %1 V. The Mg x Zn 1Àx O/ CdSe y Te 1Ày device interface was also recently studied, demonstrating improvements in J SC and efficiency due to widened bandgap and better carrier collection at low wavelengths. [13] Finding the optimum composition in Mg x Zn 1Àx O and CdSe y Te 1Ày is complicated as Mg in Mg x Zn 1Àx O and Se in CdSe y Te 1Ày both change the conduction band alignment and interface defect density, which can have significant impacts on interface recombination, barrier heights, and V OC.…”