A comprehensive investigation of the gas-phase reaction pathways of diethylzinc (DEZn) and tert-butanol (t-BuOH) during metal-organic chemical vapor deposition (MOCVD) is conducted to improve the deposition quality of thin films from a micro-mechanistic perspective. This study employs quantum chemical calculations based on density functional theory (DFT) to analyze the reaction kinetics and thermodynamics of the DEZn and t-BuOH system, in order to identify the reaction mechanism and the most probable gas-phase reaction products at different temperatures under excess t-BuOH conditions. Results indicate that the gas-phase product distribution is governed by DEZn pyrolysis. At low temperatures (), the reaction is hindered by a complexation-dominated mechanism, inhibiting Zn(OH)2 formation and resulting in poor-quality, island-like film growth. A mechanistic shift occurs at 523.15 K due to partial pyrolysis of DEZn, transitioning the system to a bimolecular collision-dominated regime yielding primarily . Optimal film quality is achieved in the complete pyrolysis zone (), where and synergistically promote ordered layered growth. These findings suggest that by utilizing temperature to modulate the supply ratio of monomers and dimers under excess t-BuOH condition, the structural properties of films can be precisely controlled.
YeWFangK. Comparative study on structure and properties of ZnO thin films prepared by RF magnetron sputtering using pure metallic Zn target and ZnO ceramic target. Surf Eng2020; 36: 49–54.
2.
YangBXuMZhangT, et al.Photoelectric properties of F-doped ZnO thin films prepared by sol-combustion. Surface Engineering2020; 36: 424–428.
3.
HaygoodKJFHarnanyDJamasri, et al.Promising CO2 gas sensor application of zinc oxide nanomaterials fabricated via HVPG technique. Heliyon2024; 10: e36692.
4.
LiJWangJPeiY, et al.Research and optimization of ZnO-MOCVD process parameters using CFD and genetic algorithm. Ceram Int2020; 46: 685–695.
5.
GritsenkoLVAbdullinKAGabdullinMT. Effect of thermal annealing on properties of polycrystalline ZnO thin films. J Cryst Growth2017; 457: 164–170.
6.
LiYLiangJLinYC. Research on MOCVD structure design and process parameters based on CFD numerical simulation. J Cryst Growth2025; 671: 128366.
7.
KarakovskayaKIDorovskikhSIVikulovaES, et al.Volatile iridium and platinum MOCVD precursors: chemistry, thermal properties, materials and prospects for their application in medicine. Coatings2021; 11: 78.
8.
ZazhigalovVOBrazhnykDVSachukOV. Photocatalytic properties of zinc oxide prepared by combustion of jellied precursor. Theor Exp Chem2023; 59: 140–145.
9.
LambDAIrvineSJC. Growth properties of thin film ZnO deposited by MOCVD with n-butyl alcohol as the oxygen precursor. J Cryst Growth2004; 273: 111–117.
10.
OleynikNAdamMKrtschilA. Metalorganic chemical vapor phase deposition of ZnO with different O-precursors. J Cryst Growth2003; 248: 14–19.
11.
ViswanathaRSantraPKDasguptaC, et al.Growth mechanism of nanocrystals in solution: ZnO, a case study. CrystEngComm2007; 98: 255501.
12.
FuYGledhillSFischerCH. Mechanistic study of the gas-phase chemistry during the spray deposition of Zn(O,S) films by mass spectrometry. Ultrason Sonochem2021; 73: 105492.
13.
MaejimaKFujitaS. Oligomerization process in MOVPE growth of ZnO. Phys. Status Solidi (C)2006; 3: 1022–1025.
14.
ThiandoumeCSalletVTribouletR, et al.Decomposition kinetics of tertiarybutanol and diethylzinc used as precursor sources for the growth of ZnO. J Cryst Growth2009; 311: 1411–1415.
15.
TamvakosAKorirKTamvakosD, et al.NO2 Gas sensing mechanism of ZnO thin-film transducers: physical experiment and theoretical correlation study. ACS Sensors2016; 1: 406–412.
16.
KimYSWonYSHagelin-WeaverH, et al.Homogeneous decomposition mechanisms of diethylzinc by Raman spectroscopy and quantum chemical calculations. J Phys Chem A2008; 112: 4246–4253.
17.
BekermannDRogallaDBeckerH, et al. Volatile, monomeric, and fluorine-free precursors for the metal organic chemical vapor deposition of zinc oxide. Eur J Inorg Chem2010; 9: 1366–1372.
18.
PatiS. Effect of VI/II gas ratio on the properties of MOCVD grown ZnO nanostructures. J Mater Sci: Mater Electron2017; 28: 1756–1761.
19.
MunkBHSchlegelHB. Molecular orbital studies of zinc oxide chemical vapor deposition: Gas-phase radical reactions. Chem Mater2006; 18: 1878–1884.
20.
LiJLaiYXuY. Process parameter analysis and parasitic reaction of ZnO grown through MOCVD. Vacuum2018; 157: 76–82.
21.
ZhengGYangAWeiH. Effects of annealing treatment on the formation of CO₂ in ZnO thin films grown by metal-organic chemical vapor deposition. Appl Surf Sci2010; 256: 2606–2610.
22.
SmithSMSchlegelHB. Molecular orbital studies of zinc oxide chemical vapor deposition: gas-phase hydrolysis of diethyl zinc, elimination reactions, and formation of dimers and tetramers. Chem Mater2003; 15: 162–166.
23.
KimYSWonYS. Investigation on reaction pathways for ZnO formation from diethylzinc and water during chemical vapor deposition. J. Sci. Bull. Korean ChemSoc 2009; 30: 1573–1578.
24.
LiJXuY. Chemical reaction-transport model of diethylzinc hydrolysis in a vertical MOCVD reactor. Appl Therm Eng2018; 136: 108–117.
25.
MaejimaKKawabataHFujitaS. Quantum Chemical Study on Interactions of Diethylzinc with Nitrous Oxide and Water for ZnO Growth by Metal–Organic Vapor Phase Epitaxy. Jpn J Appl Phys2007; 46: 7885.
26.
Li J GanHXuY. Chemical reaction mechanism of ZnO grown using DEZn and N₂O in MOCVD. CrystEngComm2018; 20: 6775–6785.
27.
GanHWangCLiJ. DFT Study on the Gas‐Phase Potential Energy Surface Crossing Mechanism of ZnO Formation from Diethylzinc and Triplet Oxygen during Metal‐Organic Chemical Vapor Deposition. ChemistrySelect2018; 3: 1961–1966.
28.
LiJGanHXuY. Chemical reaction-transport model of oxidized diethylzinc based on quantum mechanics and computational fluid dynamics approaches. RSC Adv2018; 8: 1116–1123.
29.
SalletVThiandoumeCRommeluereJF. Some aspects of the MOCVD growth of ZnO on sapphire using tert-butanol. Mater Lett2002; 53: 126–131.
30.
Van DeelenJIlliberiAKniknieB. APCVD of ZnO: Al, insight and control by modeling. Surf Coat Technol2013; 230: 239–244.
31.
OdaSTokunagaHKitajimaN. Highly oriented ZnO films prepared by MOCVD from diethylzinc and alcohols. Jpn J Appl Phys1985; 24: 1607.
32.
XuFLiuHWangQ. Study of non-isothermal pyrolysis mechanism of lignite using ReaxFF molecular dynamics simulations. Fuel2019; 256: 115884.
33.
ZhangTBhattaraiCSonY. Reaction Mechanisms of Anisole Pyrolysis at Different Temperatures: Experimental and Theoretical Studies. Energy Fuels2021; 35: 9994–10008.
34.
WangFChenJGengD. Thermal decomposition mechanism of CL-20 at different temperatures by ReaxFF reactive molecular dynamics simulations. J Phys Chem A2018; 122: 3971–3979.
35.
ZhangHJiangJFeiM. Thermal hazard characteristics and essential mechanism study of 1-hydroxybenzotriazole: Thermodynamic study combined DFT simulation. Process Saf Environ Prot2022; 168: 713–722.
LiMReimersJRFordMJ. Accurate prediction of the properties of materials using the CAM‐B3LYP density functional. J Comput Chem2021; 42: 1486–1497.
38.
ZhangHZuoRZhongT. Quantum chemistry study on gas reaction mechanism in AlN MOVPE growth. J Phys Chem A 2020; 124: 2961–2971.
39.
WuYWuRZhouX, et al.Numerical modelling on the effect of temperature on MOCVD growth of ZnO using diethylzinc and tertiarybutanol. Coatings2022; 12: 1991.
40.
ManoharanCDhanapandianSArunachalamA, et al.Physical properties of spray pyrolysized nano flower ZnO thin films. J Alloys Compd2016; 686: 616–622.
