Young Matthias J, Musgrave Charles B, George Steven M
†Department of Chemical and Biological Engineering, University of Colorado, Boulder, Colorado 80309, United States.
‡Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, United States.
ACS Appl Mater Interfaces. 2015 Jun 10;7(22):12030-7. doi: 10.1021/acsami.5b02167. Epub 2015 May 28.
The growth of Al2O3 films by atomic layer deposition (ALD) on model sp(2)-graphitic carbon substrates was evaluated following a nitrogen dioxide (NO2) and trimethylaluminum (TMA) pretreatment to deposit an Al2O3 adhesion layer. Al2O3 ALD using TMA and water (H2O) as the reactants was used to grow Al2O3 films on exfoliated highly ordered pyrolitic graphite (HOPG) at 150 °C with and without the pretreatment procedure consisting of five NO2/TMA cycles. The Al2O3 films on HOPG substrates were evaluated using spectroscopic ellipsometry and electrochemical analysis to determine film thickness and quality. These experiments revealed that five NO2/TMA cycles at 150 °C deposited an Al2O3 adhesion layer with a thickness of 5.7 ± 3.6 Å on the HOPG substrate. A larger number of NO2/TMA cycles at 150 °C deposited thicker Al2O3 films until reaching a limiting thickness of ∼80 Å. Electrochemical impedance spectroscopy (EIS) measurements revealed that five cycles of NO2/TMA pretreatment enabled the growth of high quality insulating Al2O3 films with high charge-transfer resistance after only 20 TMA/H2O Al2O3 ALD cycles. In contrast, with no NO2/TMA pretreatment, EIS measurements indicated that 100 TMA/H2O Al2O3 ALD cycles were necessary to produce an insulating Al2O3 film with high charge-transfer resistance. Al2O3 films grown after the NO2/TMA pretreatment at 150 °C were also demonstrated to have better resistance to dissolution in an aqueous environment.
通过原子层沉积（ALD）在模型sp(2) - 石墨碳基底上生长Al2O3薄膜，在进行二氧化氮（NO2）和三甲基铝（TMA）预处理以沉积Al2O3粘附层之后对其进行了评估。使用TMA和水（H2O）作为反应物的Al2O3 ALD用于在150°C下在剥离的高度有序热解石墨（HOPG）上生长Al2O3薄膜，有无由五个NO2/TMA循环组成的预处理程序。使用椭圆偏振光谱法和电化学分析对HOPG基底上的Al2O3薄膜进行评估，以确定薄膜厚度和质量。这些实验表明，在150°C下五个NO2/TMA循环在HOPG基底上沉积了厚度为5.7±3.6 Å的Al2O3粘附层。在150°C下更多数量的NO2/TMA循环沉积了更厚的Al2O3薄膜，直至达到约80 Å的极限厚度。电化学阻抗谱（EIS）测量表明，仅经过20个TMA/H2O Al2O3 ALD循环后，五个循环的NO2/TMA预处理就能使高质量绝缘Al2O3薄膜生长，且具有高电荷转移电阻。相比之下，在没有NO2/TMA预处理的情况下，EIS测量表明需要100个TMA/H2O Al2O3 ALD循环才能产生具有高电荷转移电阻的绝缘Al2O3薄膜。在150°C下经过NO2/TMA预处理后生长的Al2O3薄膜也被证明在水性环境中具有更好的抗溶解性能。
