Article
Chemistry, Physical
Jiahui Xu, Shizheng Li, Wenjing Zhang, Shang Yan, Cui Liu, Xiao Yuan, Xiaojun Ye, Hongbo Li
Summary: This study investigates the effects of deposition and annealing temperature on the growth and surface passivation of ALD-SiO2 films. Higher deposition temperature improves growth rate and refractive index, while high-temperature annealing enhances surface passivation.
APPLIED SURFACE SCIENCE
(2021)
Article
Energy & Fuels
A. Wratten, S. L. Pain, A. Yadav, E. Khorani, T. Niewelt, L. Black, G. Bartholazzi, D. Walker, N. E. Grant, J. D. Murphy
Summary: This study investigates the potential of ultra-thin HfO2 films grown by atomic layer deposition for passivating contacts to silicon. It specifically focuses on variations in film thickness and post-deposition annealing temperature. The results show that 2.2 nm thick films annealed at 475 degrees C exhibit the highest passivation quality. The effective work function of the films also decreases with decreasing thickness. A post-deposition annealing process reduces the effective work function further. The study also examines the contact resistivity in a passivating contact structure utilizing HfO2 and finds a temperature dependence on the annealing process. The lowest resistance is achieved below 375 degrees C.
SOLAR ENERGY MATERIALS AND SOLAR CELLS
(2023)
Article
Energy & Fuels
Xinyu Wang, Kun Gao, Dacheng Xu, Kun Li, Chunfang Xing, Xinliang Lou, Zhaojun Su, Xinbo Yang
Summary: Surface passivation is improved by using a boron oxide/aluminum oxide stack (BOx/Al2O3) on c-Si surfaces. The BOx/Al2O3 stacks show superior passivation quality compared to Al2O3 single layers after annealing. The optimized BOx/Al2O3 passivation stack achieves very low dark current densities on n-type and p-type Cz wafers, as well as boron-doped p+ emitters.
SOLAR ENERGY MATERIALS AND SOLAR CELLS
(2023)
Article
Physics, Applied
Ruixue Liu, Zheng Zhang, Zhen Yang, Wei Wang, Kunlun Yan, Maozhuang Song, Rongping Wang
Summary: An Er3+-doped gallium oxide amorphous film was prepared using a radio frequency magnetron sputtering method, and a waveguide was fabricated using ultraviolet lithography and inductively coupled plasma etching. On-chip optical amplification was achieved with a gain of approximately 4.7 dB in a 7 mm long waveguide.
APPLIED PHYSICS LETTERS
(2023)
Article
Nanoscience & Nanotechnology
Abigail R. Meyer, Rohan P. Chaukulkar, Noemi Leick, William Nemeth, David L. Young, Paul Stradins, Sumit Agarwal
Summary: In this study, the atomistic-level mechanism for the chemical passivation of the monocrystalline Si surface with thermally annealed Al2O3 was investigated using in situ infrared spectroscopy and photoconductance decay measurements. The results showed that surface Si-H bonds are preserved after the ALD of Al2O3 on H-terminated Si, and restructuring occurs at the c-Si/Al2O3 interface during annealing to form interfacial SiOx. Isotope labeling was used to differentiate interfacial SiD bonds on the c-Si surface from H incorporated in Al2O3, and no net migration of atomic H or D from Al2O3 to the c-Si/Al2O3 interface was observed within the sensitivity of the infrared setup. Passivation studies were also conducted on c-Si/SiO2/Al2O3 stacks, revealing that an O-2-containing atmosphere led to the best surface chemical passivation.
ACS APPLIED NANO MATERIALS
(2021)
Article
Chemistry, Physical
Xiaokang Wan, Yunbo Xu, Xianyun Wang, Xiangjiu Guan, Yanming Fu, Chao Hu, Haowei Hu, Nai Rong
Summary: Plasma enhanced atomic layer deposition and subsequent removal of Al2O3 ultrathin overlayers on bismuth vanadate were utilized to passivate surface states and enhance PEC performance significantly. The modified BiVO4 showed a 73% increase in photocurrent density compared to unmodified BiVO4, demonstrating a novel strategy for surface modification of semiconductors in photoelectrochemical energy conversion.
APPLIED SURFACE SCIENCE
(2022)
Article
Chemistry, Multidisciplinary
Armin Richter, Hemangi Patel, Christian Reichel, Jan Benick, Stefan W. Glunz
Summary: This study evaluates the effect of various plasma treatments during the ALD deposition of Al2O3/SiO2 multilayers on the passivation quality of the silicon surface. Plasma treatments after SiO2 deposition, particularly for single Al2O3/SiO2 bilayers treated with H-2 plasma, significantly improve the surface passivation quality. The improved passivation quality comes from enhanced chemical interface passivation rather than an improved field effect.
ADVANCED MATERIALS INTERFACES
(2023)
Article
Nanoscience & Nanotechnology
Piotr Caban, Rafal Pietruszka, Jaroslaw Kaszewski, Monika Ozga, Bartlomiej S. Witkowski, Krzysztof Kopalko, Piotr Ku zmiuk, Katarzyna Gwozdz, Ewa Placzek-Popko, Krystyna Lawniczak-Jablonska, Marek Godlewski
Summary: In this study, the effects of different treatments on the surface of gallium arsenide on the external quantum efficiency of photovoltaic cells have been investigated through experiments. Various characterization techniques such as AFM, SEM, XPS, PL, and bandgap measurements were employed to analyze device structures and interface changes. The results showed that the highest EQE value was achieved by initially etching the samples with a citric acid-based etchant, followed by either sulfur passivation or ammonium hydroxide treatment.
BEILSTEIN JOURNAL OF NANOTECHNOLOGY
(2021)
Article
Energy & Fuels
Hongyan Xu, Nasrin Siraj Lopa, Mohammad Karbalaei Akbari, Di Wu, Jie Hu, Serge Zhuiykov
Summary: Two-dimensional conformal SnO2-Ga2O3 n-p heterostructures were fabricated on a wafer scale using atomic layer deposition. After annealing at 250 degrees C for 1 h in air, the heterostructures exhibited a high specific capacitance of 167 F g-1 at a current density of 7.69 A g-1. Even after 10,000 continuous cycles, the sub-10 nm thick heterostructures demonstrated a high capacitance retention of -92.55%. These findings highlight the potential of ultra-thin 2D SnO2-Ga2O3 heterostructures for high-performance energy storage devices.
JOURNAL OF ENERGY STORAGE
(2023)
Article
Energy & Fuels
Bart Macco, Mike L. van de Poll, Bas W. H. van de Loo, Tim M. P. Broekema, Saravana B. Basuvalingam, Cristian A. A. van Helvoirt, Wilhelmus J. H. Berghuis, Roel J. Theeuwes, Nga Phung, Wilhelmus M. M. Kessels
Summary: Recently, it has been shown that stacks consisting of ultrathin SiO2 coated with ALD Al-doped zinc oxide (ZnO:Al) can achieve excellent passivation and low contact resistivity. This study investigates the required thicknesses of ZnO and Al2O3 capping layer for high passivation levels, and demonstrates selective removal of Al2O3 layer from ZnO:Al. Furthermore, it highlights the potential of spatial ALD for industrial applications and the selective deposition of ZnO:Al on oxidized regions of a c-Si surface.
SOLAR ENERGY MATERIALS AND SOLAR CELLS
(2022)
Article
Energy & Fuels
Bart Macco, Bas W. H. van de Loo, Marc Dielen, Dennis G. J. A. Loeffen, Bart B. van Pelt, Nga Phung, Jimmy Melskens, Marcel A. Verheijen, Wilhelmus M. M. Kessels
Summary: Research has shown that stacks consisting of ultrathin SiO2 coated with ALD ZnO and Al2O3 provide state-of-the-art passivation for n-type crystalline silicon surfaces and additional functionalities for silicon solar cells. The Al2O3 capping layer is crucial in the passivation mechanism, while annealing can significantly improve the transparency and lateral conductivity of ZnO.
SOLAR ENERGY MATERIALS AND SOLAR CELLS
(2021)
Article
Energy & Fuels
Ailish Wratten, Sophie L. Pain, David Walker, Arne Benjamin Renz, Edris Khorani, Tim Niewelt, Nicholas E. Grant, John D. Murphy
Summary: This study investigates the effective surface passivation mechanism of silicon with hafnium oxide thin films grown via atomic layer deposition (ALD). The study finds that postdeposition annealing can activate the passivation, with the most effective temperature being 475°C. The passivation level continues to increase with higher annealing temperatures, reaching a peak at 475°C, and then decreases above this temperature due to a loss of chemical passivation.
IEEE JOURNAL OF PHOTOVOLTAICS
(2023)
Article
Chemistry, Multidisciplinary
Sophie L. Pain, Edris Khorani, Tim Niewelt, Ailish Wratten, Galo J. Paez Fajardo, Ben P. Winfield, Ruy S. Bonilla, Marc Walker, Louis F. J. Piper, Nicholas E. Grant, John D. Murphy
Summary: Ultra-thin passivating films of SiO2, Al2O3, and HfO2 were created through plasma-enhanced atomic layer deposition and annealing. It was found that thin negatively charged HfO2 layers exhibited excellent passivation properties, making them a promising candidate for future passivating contacts in high-efficiency silicon solar cells.
ADVANCED MATERIALS INTERFACES
(2022)
Article
Chemistry, Physical
Ching-Hui Hsu, Da-Yao Lao, Likarn Wang
Summary: In this study, AlOx passivation layers on the rear sides of silicon PERC solar cells are formed by thermally oxidizing 3 nm-thick aluminum films. The oxidation process is conducted in a furnace full of oxygen at 400 degrees C for 10 minutes, followed by annealing at 700 degrees C for 3 minutes and then stacking SiNx films on the back surfaces. A second annealing process is done at 400 degrees C for 10 minutes to repair the defects resulting from ion bombardment on the passivation layer. With the thermal oxidation method, an AlOx passivation layer with a negative charge density of -3.21 x 10(12) cm(-2) was confirmed for an annealed sample, compared to -6.17 x 10(11) cm(-2) for an unannealed sample.
INTERNATIONAL JOURNAL OF PHOTOENERGY
(2023)
Article
Chemistry, Multidisciplinary
Ran Zhao, Kai Zhang, Jiahao Zhu, Shuang Xiao, Wei Xiong, Jian Wang, Tanghao Liu, Guichuan Xing, Kaiyang Wang, Shihe Yang, Xinwei Wang
Summary: Lowering the deposition temperature of ALD was found to reduce the degradation of the MAPbI(3) perovskite surface, with the best temperature identified as 75 degrees C. Solar cells with ALD Al2O3 interlayers deposited at 75 degrees C exhibited significantly enhanced power conversion efficiency, indicating the effectiveness of the ALD layer in passivating defect states at the perovskite surface.
NANOSCALE ADVANCES
(2021)
