Effects of Moisture-Proof Back Passivation Layers of Al2O3 and AlxTi1–xOy Films on Efficiency Improvement and Color Modulation in Transparent a-Si:H Solar Cells

Pujar

et al. 2021

Adv Elect Materials

2D transition metal dichalcogenides (TMDs) have recently received significant attention owing to their superior electrical, optical, and mechanical properties. However, most previous research on TMDs has not focused on their stability against bias and illumination stress. Here, high‐stability tungsten diselenide (WSe2) field‐effect transistors (FETs) are introduced with an ultrathin Al‐assisted alumina (Al2O3) passivation. Through the Al‐assisted Al2O3 passivation, the transport behavior of the WSe2 FETs is converted from p‐type to ambipolar owing to the n‐type doping effect of Al2O3 passivation. Furthermore, the stability of the WSe2 FETs is highly improved against gate bias and illumination stress owing to the effect of Al2O3 film quality on WSe2 by ultrathin Al predeposition (≈1 nm). To compare the stress effect on the electrical characteristics, three types of devices: 1) pristine WSe2 FETs, 2) WSe2 FET with Al2O3 passivation layer, and 3) WSe2 FETs with Al‐assisted Al2O3 passivation layer, are systematically tested with positive gate bias stress (PBS) and positive gate bias illumination stress (PBIS). Finally, an ambipolar inverter composed of Al‐assisted Al2O3 passivated WSe2 FETs is demonstrated. This study proposes a promising approach that improves the stability of TMD‐based FETs for next‐generation logic applications.

Section: Resultsmentioning

confidence: 99%

Ultrathin Al‐Assisted Al₂O₃ Passivation Layer for High‐Stability Tungsten Diselenide Transistors and Their Ambipolar Inverter

Pujar

et al. 2021

Adv Elect Materials

“…Extensive research has been conducted on aluminum oxide as a thin-film material with diverse applications, including protective coatings [1,2], diffusion barriers [3][4][5], and electronic and optical devices [6][7][8][9]. Crystalline Al 2 O 3 films offer clear advantages in applications that require elevated chemical stability [2,10], specific optical or electronic attributes [7,11,12], and superior mechanical properties [13,14].…”

Section: Introductionmentioning

confidence: 99%

Study of Mid-Pressure Ar Radiofrequency Plasma Used in Plasma-Enhanced Atomic Layer Deposition of α-Al2O3

Piller,

Raud,

Aarik

et al. 2024

Processes

This study investigated the characteristics of radiofrequency, middle-pressure argon plasma used in the atomic layer deposition (ALD) of Al2O3 films. Based on the electrical characteristics—the current, voltage, and phase shift between them—and the stability of the plasma plume, the optimum plasma power, allowing reliable switching on of the plasma for any step of an ALD cycle, was determined. Spectral measurements were performed to determine the gas temperature and reactive species that could be important in the ALD process. The density of metastable argon atoms was estimated using tunable laser absorption spectroscopy. It was concluded that plasma heating of substrates did not affect film growth. The crystallization-enhancing effect of plasma observed in these experiments was due to the action of OH radicals produced in the plasma.

ACS Appl. Energy Mater.

“…We also introduced a hole-transport buffer layer of MoOx to reduce carrier recombination at the p/i interface. Using the optimized MoOx bilayer, the figure of merit (FOM) of the transparent solar cell, which is expressed as the product of the power conversion efficiency (PCE) and transmittance, ,, was determined for the thickness of the absorption layer. Monolithic serial modularization using laser scribing was performed under the highest FOM condition.…”

Section: Introductionmentioning

confidence: 99%

Optimization of a Molybdenum Oxide Bilayer Facilitating Hole Transfer in the p/i Interface for Transparent Thin-Film Silicon Solar Cells and Modules Using Laser Scribing

Choi

Seo

Kim

et al. 2023

Transparent hydrogenated amorphous silicon solar cells were fabricated using a p-type window layer of molybdenum oxide (MoOx) for building-integrated photovoltaic (BIPV) windows. The MoOx layer was prepared with oxygen flow ratios from 0.03 to 0.21 by reactive sputtering, and the PV performance was improved using MoOx with an oxygen flow ratio of 0.09 because of the lower carrier recombination and parasitic absorption in the p layer. Additionally, we optimized the cell by introducing a MoOx bilayer, and the power conversion efficiency of the cell using an optimized MoOx bilayer was enhanced by boosted open circuit voltage through facilitating hole transfer. To realize the application of the BIPV window, we manufactured a monolithic connected solar module using the laser scribing process, and the cell-to-module loss was approximately 22.9%. Because MoOx remained after the P2 scribing process, residual MoOx played a role in the deterioration of the series resistance.