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Liao MW, Jeng HT, Perng TP. Formation Mechanism and Bandgap Reduction of GaN-ZnO Solid-Solution Thin Films Fabricated by Nanolamination of Atomic Layer Deposition. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2207849. [PMID: 36495592 DOI: 10.1002/adma.202207849] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2022] [Revised: 11/14/2022] [Indexed: 06/17/2023]
Abstract
Nanolamination of GaN and ZnO layers by atomic layer deposition (ALD) is employed to fabricate GaN-ZnO homogenous solid-solution thin films because it offers more precise control of the stoichiometry. By varying the ALD cycle ratios of GaN:ZnO from 5:10 to 10:5, the (GaN)1- x (ZnO)x films with 0.39 ≦ x ≦ 0.79 are obtained. The formation of solid solution is explained based on the atomic stacking and preferred orientation of the layers of GaN and ZnO. However, the growth rates of GaN and ZnO during the lamination process are different from those of pure GaN and ZnO films. It is found that GaN grows faster on ZnO, whereas ZnO grows slower on GaN. The density functional theory (DFT) calculations are performed using a superlattice model for GaN and ZnO laminated layers fabricated by ALD to understand the difference of density of states (DOS) and evaluate the bandgaps for various atomic configurations in the solid-solution films. The band positions are experimentally defined by ultraviolet photoelectron spectroscopy. Significant bandgap reduction of the solid solutions is observed, which can be explained by the DOS from the DFT calculations. Visible-light-driven photocatalytic hydrogen evolution is conducted to confirm the applicability of the solid-solution films.
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Affiliation(s)
- Ming-Wei Liao
- Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu, 30013, Taiwan
| | - Horng-Tay Jeng
- Department of Physics, National Tsing Hua University, Hsinchu, 30013, Taiwan
- Physics Division, National Center for Theoretical Sciences, Taipei, 10617, Taiwan
- Institute of Physics, Academia Sinica, Taipei, 11529, Taiwan
| | - Tsong-Pyng Perng
- Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu, 30013, Taiwan
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Chen J, Zhao J, Feng S, Zhang L, Cheng Y, Liao H, Zheng Z, Chen X, Gao Z, Chen KJ, Hua M. Formation and Applications in Electronic Devices of Lattice-Aligned Gallium Oxynitride Nanolayer on Gallium Nitride. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2208960. [PMID: 36609822 DOI: 10.1002/adma.202208960] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 12/12/2022] [Indexed: 06/17/2023]
Abstract
Gallium nitride (GaN), a promising alternative semiconductor to Si, is widely used in photoelectronic and electronic technologies. However, the vulnerability of the GaN surface is a critical restriction that hinders the development of GaN-based devices, especially in terms of device stability and reliability. In this study, this challenge is overcome by converting the GaN surface into a gallium oxynitride (GaON) epitaxial nanolayer through an in situ two-step "oxidation-reconfiguration" process. The O plasma treatment overcomes the chemical inertness of the GaN surface, and sequential thermal annealing manipulates the kinetic-thermodynamic reaction pathways to create a metastable GaON nanolayer with a wurtzite lattice. The GaN-derived GaON nanolayer is a tailored structure for surface reinforcement and possesses several advantages, including a wide bandgap, high thermodynamic stability, and large valence band offset with a GaN substrate. These physical properties can be further leveraged to enhance the performance of GaN-based devices in various applications, such as power systems, complementary logic integrated circuits, photoelectrochemical water splitting, and ultraviolet photoelectric conversion.
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Affiliation(s)
- Junting Chen
- Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, 518055, China
- Department of Electronic and Computer Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, 999077, China
| | - Junlei Zhao
- Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Sirui Feng
- Department of Electronic and Computer Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, 999077, China
| | - Li Zhang
- Department of Electronic and Computer Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, 999077, China
| | - Yan Cheng
- Department of Electronic and Computer Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, 999077, China
| | - Hang Liao
- Department of Electronic and Computer Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, 999077, China
| | - Zheyang Zheng
- Department of Electronic and Computer Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, 999077, China
| | - Xiaolong Chen
- Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Zhen Gao
- Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Kevin J Chen
- Department of Electronic and Computer Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, 999077, China
| | - Mengyuan Hua
- Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, 518055, China
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Large-Sized Nanocrystalline Ultrathin β-Ga2O3 Membranes Fabricated by Surface Charge Lithography. NANOMATERIALS 2022; 12:nano12040689. [PMID: 35215016 PMCID: PMC8880476 DOI: 10.3390/nano12040689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Revised: 02/12/2022] [Accepted: 02/16/2022] [Indexed: 02/04/2023]
Abstract
Large-sized 2D semiconductor materials have gained significant attention for their fascinating properties in various applications. In this work, we demonstrate the fabrication of nanoperforated ultrathin β-Ga2O3 membranes of a nanoscale thickness. The technological route includes the fabrication of GaN membranes using the Surface Charge Lithography (SCL) approach and subsequent thermal treatment in air at 900 °C in order to obtain β-Ga2O3 membranes. The as-grown GaN membranes were discovered to be completely transformed into β-Ga2O3, with the morphology evolving from a smooth topography to a nanoperforated surface consisting of nanograin structures. The oxidation mechanism of the membrane was investigated under different annealing conditions followed by XPS, AFM, Raman and TEM analyses.
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Fatahilah MF, Yu F, Strempel K, Römer F, Maradan D, Meneghini M, Bakin A, Hohls F, Schumacher HW, Witzigmann B, Waag A, Wasisto HS. Top-down GaN nanowire transistors with nearly zero gate hysteresis for parallel vertical electronics. Sci Rep 2019; 9:10301. [PMID: 31311946 PMCID: PMC6635513 DOI: 10.1038/s41598-019-46186-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 06/24/2019] [Indexed: 12/03/2022] Open
Abstract
This paper reports on the direct qualitative and quantitative performance comparisons of the field-effect transistors (FETs) based on vertical gallium nitride nanowires (GaN NWs) with different NW numbers (i.e., 1–100) and diameters (i.e., 220–640 nm) fabricated on the same wafer substrate to prove the feasibility of employing the vertical 3D architecture concept towards massively parallel electronic integration, particularly for logic circuitry and metrological applications. A top-down approach combining both inductively coupled plasma dry reactive ion etching (ICP-DRIE) and wet chemical etching is applied in the realization of vertically aligned GaN NWs on metalorganic vapor-phase epitaxy (MOVPE)-based GaN thin films with specific doping profiles. The FETs are fabricated involving a stack of n-p-n GaN layers with embedded inverted p-channel, top drain bridging contact, and wrap-around gating technology. From the electrical characterization of the integrated NWs, a threshold voltage (Vth) of (6.6 ± 0.3) V is obtained, which is sufficient for safely operating these devices in an enhancement mode (E-mode). Aluminium oxide (Al2O3) grown by atomic layer deposition (ALD) is used as the gate dielectric material resulting in nearly-zero gate hysteresis (i.e., forward and backward sweep Vth shift (ΔVth) of ~0.2 V). Regardless of the required device processing optimization for having better linearity profile, the upscaling capability of the devices from single NW to NW array in terms of the produced currents could already be demonstrated. Thus, the presented concept is expected to bridge the nanoworld into the macroscopic world, and subsequently paves the way to the realization of innovative large-scale vertical GaN nanoelectronics.
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Affiliation(s)
- Muhammad Fahlesa Fatahilah
- Institute of Semiconductor Technology (IHT), Technische Universität Braunschweig, Hans-Sommer-Straße 66, D-38106, Braunschweig, Germany. .,Laboratory for Emerging Nanometrology (LENA), Technische Universität Braunschweig, Langer Kamp 6, D-38106, Braunschweig, Germany.
| | - Feng Yu
- Institute of Semiconductor Technology (IHT), Technische Universität Braunschweig, Hans-Sommer-Straße 66, D-38106, Braunschweig, Germany.,Laboratory for Emerging Nanometrology (LENA), Technische Universität Braunschweig, Langer Kamp 6, D-38106, Braunschweig, Germany
| | - Klaas Strempel
- Institute of Semiconductor Technology (IHT), Technische Universität Braunschweig, Hans-Sommer-Straße 66, D-38106, Braunschweig, Germany.,Laboratory for Emerging Nanometrology (LENA), Technische Universität Braunschweig, Langer Kamp 6, D-38106, Braunschweig, Germany
| | - Friedhard Römer
- Computational Electronics and Photonics (CEP), University of Kassel, Wilhelmshöher Allee 71, D-34121, Kassel, Germany
| | - Dario Maradan
- Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, D-38116, Braunschweig, Germany
| | - Matteo Meneghini
- Department of Information Engineering, University of Padua, 35131, Padua, Italy
| | - Andrey Bakin
- Institute of Semiconductor Technology (IHT), Technische Universität Braunschweig, Hans-Sommer-Straße 66, D-38106, Braunschweig, Germany.,Laboratory for Emerging Nanometrology (LENA), Technische Universität Braunschweig, Langer Kamp 6, D-38106, Braunschweig, Germany
| | - Frank Hohls
- Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, D-38116, Braunschweig, Germany
| | - Hans Werner Schumacher
- Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, D-38116, Braunschweig, Germany
| | - Bernd Witzigmann
- Computational Electronics and Photonics (CEP), University of Kassel, Wilhelmshöher Allee 71, D-34121, Kassel, Germany
| | - Andreas Waag
- Institute of Semiconductor Technology (IHT), Technische Universität Braunschweig, Hans-Sommer-Straße 66, D-38106, Braunschweig, Germany.,Laboratory for Emerging Nanometrology (LENA), Technische Universität Braunschweig, Langer Kamp 6, D-38106, Braunschweig, Germany
| | - Hutomo Suryo Wasisto
- Institute of Semiconductor Technology (IHT), Technische Universität Braunschweig, Hans-Sommer-Straße 66, D-38106, Braunschweig, Germany. .,Laboratory for Emerging Nanometrology (LENA), Technische Universität Braunschweig, Langer Kamp 6, D-38106, Braunschweig, Germany.
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