A revolutionary new material turns semiconductors sustainable
Revolutionary new material turns semiconductors sustainable
Semiconductors are materials that we find at the heart of all the electronic devices around us, such as televisions and mobile phones. Without them, our computers would not be able to process or retain data, and LED lights, for example, would lose their ability to shine. This is in contrast to solar panels, which rely heavily on semiconductors.
Semiconductors are materials characterized by a set of unique properties, the most important of which is the difficulty of transmitting electric current through them; Which means that this current can be easily controlled by adding other materials to the semiconductor, which opened the way for an unprecedented electronic and computer revolution, and made the semiconductor industry a national security for the great powers.
Although a simple component such as sand (Silicon) is the material most used to manufacture semiconductors, we find that this manufacturing process is not as simple as itself, as it consumes huge amounts of energy; In order to reach high temperatures exceeding 1500 degrees Celsius. Add to this the processes of extracting and transporting the raw materials used in the semiconductor industry from their original places to the manufacturing countries, which take weeks or even many months.
The above has made the scientific community hungry for a sustainable way to manufacture semiconductors. In order to achievedevelopment goalsin our contemporary world, in addition to achieving sustainability at the same time. Perhaps the most prominent recent efforts of the scientific community in this context is the substance “Multielement ink,” which we will try to shed light on in some detail in this article.
How do semiconductors work?
In traditional metal conductors, current is transmitted by the movement of electrons from point to point, a process that depends on the conductive properties of each material, and control over this movement is limited. As for semiconductors, the electric current is transmitted through the movement of a stream of electrons heading to the positive pole, accompanied by a stream of holes (positively charged) within the atomic structure of the material, heading to the negative pole.
The above cannot happen in pure forms of semiconductor elements such as silicon, where their atoms are connected by stable covalent bonds. So impurities of specific other elements are introduced, so that these semiconductors become able to conduct current, in a process known as doping.
These impurities, including the elements phosphorus and boron, bind - for example - to silicon atoms, creating a group of gaps (empty places in the outer orbit of the atoms), which stimulates the movement of electrons - in general - in the system, as well as the movement of these positive gaps.
The unique feature of the way semiconductors work is that we can tame and control the electric current; We will then be able to adapt electricity to various applications, and this is by choosing the type of semiconductor material, and determining the impurities in the appropriate quantity.
New scientific breakthrough
Multi-component ink is a material that can make the semiconductor manufacturing process less energy-intensive than heat; Therefore, more sustainable. This type of semiconductor was developed by researchers at Lawrence Berkeley National Laboratory and the University of California, Berkeley, and is the first “high-entropy” semiconductor that can be processed at temperatures as low as room temperature. This scientific breakthrough was recently published in the journal Nature.
Bidong Yang, the study’s lead researcher, said: “The traditional method of making semiconductors consumes a lot of energy, and is one of the main sources of carbon emissions.” It is worth noting that Yang is a senior scientist in the Materials Science Department at Berkeley Lab, and a professor of chemistry, materials science and engineering at the University of California, Berkeley.
This scientific breakthrough is based on two unique families of semiconductor materials: hard alloys made of high-entropy semiconductors, and soft and flexible halide perovskite crystals.
High-entropy materials are solids made of five or more different chemical elements that self-assemble in nearly equal proportions into a single system. For many years researchers have wanted to use high-entropy materials; To develop semiconductor materials that self-assemble with minimal energy input. By self-assembly we mean that the molecules of the elements are arranged together in a specific way without any external interference.
Unique properties of perovskite halide
For a long time, high-entropy semiconductors have not received sufficient study and attention in the scientific community in the past decades, which is a major problem in itself, in addition to the fact that traditional high-entropy alloys - although they require much less energy than silicon for manufacturing - still require very high temperatures exceeding 1000 degrees Celsius, which makes relying on them in manufacturing processes on a commercial scale a difficult challenge.
To overcome this challenge, Yang and his team took advantage of the unique properties of the halide perovskite material, which has been the subject of numerous studies previously; Due to their use in solar panels.
Perovskite is easily processed from solution at low temperatures, ranging from room temperature to 150°C; This means there is no need to consume large amounts of thermal energy to process this unique material, which means reducing the cost of manufacturing semiconductors, in addition to making this vital industry more sustainable.
In this new study, Yang and his team took advantage of lower energy requirements; To produce single crystals of high-entropy perovskite halide from solution at moderate temperature conditions. Yang explained that because of their ionic bonding nature, perovskite halide crystal structures require much less energy to form than other material systems.
Experiments conducted at Berkeley Lab have confirmed that the resulting octahedral and cubic crystals are, in fact, single crystals of high-entropy perovskite halide, and these crystals vary in composition; Some of them are composed of five elements, others are composed of six elements, and the diameter of the crystals ranges between 30 - 100 micrometers. (A micrometer is a billionth of a metre, which is roughly the size of a dust speck.)
Sustainable Semiconductors
This new method of producing single-crystal semiconductors at normal temperatures occurs within a few hours of mixing the solution; The crystals are then deposited, which is much faster than traditional semiconductor manufacturing techniques.
It is worth noting that the perovskite halide had previously suffered from stability problems at ambient temperatures, which made it impossible to manufacture it on a commercial scale for many years. However, the high-entropy perovskite halide surprised the research team with its impressive stability in the ambient air, lasting at least six months!
Yang said: This multi-component ink could be used in a number of potential applications, especially multi-colored LEDs and other lighting devices, and this material could also serve as a programmable component in optical computing devices, which use light to transmit or store data.
