雅思阅读 178: The Thinnest Material Ever Made（被制造出来的最薄材料）

改编自 Science / Paragraf / arXiv（2025-2026年）。雅思阅读 Section 3 难度，约 1050 词。 素材来源：https://www.science.org/doi/abs/10.1126/science.aed9202

Reading Passage

A. Graphene was discovered by accident in 2004, when two physicists at the University of Manchester used ordinary sticky tape to peel thin layers off a block of graphite. The trick, simple enough that a schoolchild could repeat it, produced a sheet of carbon just one atom thick — and revealed properties that physicists had spent decades debating whether such a thing could even possess. The electrons in graphene travel through the sheet as if they had no mass, at speeds a fraction below that of light; the material conducts heat better than diamond; it is stronger than steel by weight and yet flexible enough to wrap around a fibre. It is also transparent, because a single atomic layer absorbs only a few percent of the light that hits it. For two decades, graphene has occupied an odd position in the public imagination: endlessly touted as a miracle substance, endlessly delayed in reaching the market. The reason, as researchers are now acknowledging, has less to do with graphene's intrinsic properties than with the difficulty of making it well. The story of graphene is, in this sense, the story of every material that has ever moved from a laboratory demonstration to a commercial product: the science was easy, the engineering was hard, and the gap between the two absorbed nearly two decades.

B. The core problem is the one that has dogged every new material since the invention of the silicon chip: scale. A single flake of graphene, peeled off in a laboratory and measured under a microscope, can be near-perfect. A square metre of the stuff, grown by chemical vapour deposition on a copper foil and transferred to a glass slide, is riddled with defects — wrinkles, tears, microscopic grains where the crystal lattice changes direction, and residues from the transfer process itself. Each defect scatters electrons, degrades transparency, and shortens device life. For years the compromise was tolerated: researchers made sensors, prototypes and demonstration devices on small pieces, while manufacturers waited for a process that could produce a uniform film across a wafer the size of a silicon chip. In 2025 and early 2026, that wait began to end. A UK-based company announced the production of a six-inch graphene wafer at its new factory, growing graphene directly on silicon using standard semiconductor equipment. Simultaneously, a group in China reported patch-free single-crystal monolayers grown on silicon carbide, while a Beijing team published a Science paper on the deterministic growth of pure-phase rhombohedral graphene, a stacked arrangement long predicted to be superconducting but never before controllably synthesised.

C. The rhombohedral work deserves a closer look, because it illustrates how subtle a problem two-dimensional materials present. When layers of graphene are stacked, they can be placed in different relative alignments — hexagonal, Bernal or rhombohedral — and the electronic properties depend on the alignment in ways that are exquisitely sensitive to tiny slips between layers. For decades, samples of rhombohedral graphene could be grown only in small, mixed patches, because the growth process did not control which stacking order emerged. The Beijing team solved this by exploiting the geometry of the steps on the silicon carbide surface: they designed a substrate whose step edges guided each new layer into the correct registration. The result, published in July 2026, was a sample of pure rhombohedral phase more than 99 percent, large enough — 160 by 80 micrometres — to allow the first comprehensive reference measurements of its Raman spectra and intrinsic electrical properties. That may sound small. In the world of two-dimensional crystals, it is the difference between a laboratory curiosity and a material one can actually characterise.

D. What will graphene be used for? The most immediate applications are not the flexible phones of popular imagination but the quiet ones. Graphene field-effect transistors made on silicon wafers have already found their way into highly sensitive magnetic-field sensors for medical imaging and into the transparent electrodes that improve the current spreading in gallium-nitride light-emitting diodes. A 2025 study demonstrated two-inch, transfer-free patterned graphene electrodes on LED chips, showing that graphene improved both contact and light output. Because the material is so thin and so sensitive to its chemical environment, it also excels as a gas sensor — a 2025 paper used oxygen-plasma-treated graphene on silicon carbide to detect nitrogen dioxide at concentrations far below the regulatory limit. Hybrid structures, in which graphene is stacked on perovskite oxides or transition-metal dichalcogenides, promise photodetectors and solar cells that combine graphene's conductivity with other materials' light absorption. None of these applications replaces silicon; they supplement it.

E. The broader significance of graphene lies less in any single product than in what it opened: a family of two-dimensional materials. Once physicists knew that a single atomic layer could be isolated and studied, they asked why not others. Today there are hundreds of predicted and partially synthesised two-dimensional crystals — hexagonal boron nitride, molybdenum disulphide, phosphorene, the biphenylene networks announced in late 2025 — each with its own band structure and mechanical behaviour. Some are semiconductors with band gaps tuned for transistors; some are insulators perfect for tunnelling barriers; some are predicted topological superconductors. The field is approaching the moment that silicon reached in the 1950s, when the question was no longer whether the material existed but whether it could be manufactured consistently. The 2026 results — the six-inch wafer, the patch-free monolayer, the pure rhombohedral phase — are the first credible signs that the answer is yes. The miracle substance, twenty years on, is finally becoming an ordinary one, and ordinary is exactly what a technology needs in order to matter. The most important graphene product of the next decade may not be a single headline device at all; it may simply be the invisible layer in a sensor, an electrode or a chip that nobody except an engineer knows is there.

Questions 1-4

Choose the correct heading for paragraphs B, C, D and E from the list of headings below.

List of Headings i. Why graphene's promise outran its production — and the 2025-2026 breakthroughs ii. How sticky tape first isolated a single atomic layer iii. A closer look at controlled rhombohedral stacking iv. Quiet, immediate applications in sensors and electrodes v. Why graphene will replace silicon entirely vi. The rise of the wider family of two-dimensional materials vii. The history of carbon research

1. Paragraph B: ____
2. Paragraph C: ____
3. Paragraph D: ____
4. Paragraph E: ____

Questions 5-8

Choose the correct letter, A, B, C or D.

5. How was graphene first isolated? A. By chemical vapour deposition on copper. B. By peeling layers off graphite using sticky tape. C. By melting diamond at high pressure. D. By growing crystals from solution.

6. What has been the central practical difficulty with graphene? A. It is too expensive to extract from ore. B. Scaling it up uniformly without defects has proved hard. C. It melts at room temperature. D. It cannot be used with silicon.

7. Why was the rhombohedral graphene result important? A. It was the first superconducting material ever made. B. It allowed deterministic control of layer stacking, producing a >99% pure phase. C. It proved graphene cannot be stacked. D. It replaced silicon carbide.

8. What does the author say about graphene's likely applications? A. They will immediately replace silicon in all chips. B. They are quiet ones — sensors, LED electrodes, gas detectors — that supplement silicon. C. They are limited to flexible phones. D. They will not be commercially viable.

Questions 9-13

Do the following statements agree with the claims of the writer?

Write:

• TRUE if the statement agrees with the information
• FALSE if the statement contradicts the information
• NOT GIVEN if there is no information on this

9. A single layer of graphene absorbs only a few percent of visible light.
10. The UK company announced a 12-inch graphene wafer in 2025.
11. Rhombohedral graphene is a stacking arrangement in which layers are slip-aligned.
12. Graphene is now routinely used as the main material in central processing units.
13. The wider family of 2D materials includes boron nitride and molybdenum disulphide.

Questions 14-15

Complete the summary below using NO MORE THAN TWO WORDS from the passage.

Graphene was first isolated in 2004 by peeling layers from graphite. The long-standing problem was producing it at (14) __________ without wrinkles, tears and grain (15) __________. Recent results — a six-inch wafer, a patch-free single crystal and pure rhombohedral phase — suggest the material is at last becoming manufacturable.

答案与解析

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