Atomically precise manufacturing

Atomically Precise Manufacturing (APM) is an experimental application of nanotechnology where single atoms and molecules can be precisely positioned to form products that are completely without flaw, down to the atomic level. The technology currently has potential in highly technical fields like quantum computing, but if commercialized, would likely have major impact across all fields of manufacturing. APM is classified as a disruptive technology, or a technology that creates large amounts of change in existing industry.^[1][2]

APM is still currently under development and no easy method to manipulate atoms has been discovered. Once advancements have been made and the technology becomes cheap and efficient, APM can be commercialized for large-scale usage and will lower the costs and energy requirements of manufacturing. As a disruptive technology, APM will first be marketed in niche fields such as nanomedicine and quantum computing before seeing widespread use.^[1]

Advantages of Atomically Precise Manufacturing[]

Traditional manufacturing processes are mainly based around the concepts of discrete and process manufacturing. Discrete manufacturing is a manufacturing methodology that produces finished, mass-produced goods made from pre-assembled components in an assembly line. Any product made via discrete manufacturing can be broken down into the components used to assemble it. Process manufacturing can be seen as the opposite. In process manufacturing, the manufacturer must follow a set recipe to create finished goods like food or drugs. Products made in this way cannot be broken down further into its constituents. But while both of these manufacturing methods are excellent for rapidly mass-producing goods, they often are wasteful, inefficient, and cannot be used to create products that require an extreme degree of preciseness due to their large-scale nature.^[3]

Atomically precise manufacturing, however, has the level of precision to create extremely sensitive products. In industries where exactness is critical, atomically precise manufacturing has potential to be a revolutionary force. For example, in the growing field of quantum technology and computing, the development of nanoplasmonic devices is underway. In these devices, even a small amount of impreciseness in the gaps between particles has huge implications on the end result. The concepts of APM allow for precise manipulation of particles to ensure developers and researchers can get correct results.^[4]

Applications[]

The concepts of APM can be applied to many fields of research and development and some of the more promising applications are listed below.

Environmental[]

APM also has potential to aid in solving many of the environmental issues society is currently dealing with. Incorporation of APM into manufacturing processes globally could greatly reduce the amount of pollution created by industry currently. By operating at the atomic level, the efficiency of manufacturing can be greatly increased and waste can be exponentially decreased because manufacturers now have almost complete control over every aspect of the manufacturing process.^[5]

APM can also be help with the widespread implementation of renewable energy sources. For example, APM has the potential to greatly increase the productivity of photovoltaic systems (solar energy). Currently, photovoltaic (PV) systems are too costly for the amount of energy they produce to be used as a primary method of generating energy for large urban areas. The hope is that APM will allow PV systems to be created from cheaper, more common materials and eventually be able to phase out fossil fuels as the primary form of energy generation.^[5]

The removal of carbon dioxide from the atmosphere is another potential application for APM. Currently, the technology to remove carbon dioxide from the air exists, but is inconvenient to use in great quantities. APM could be used to make this technology more accessible.^[5]

Quantum Computing[]

Currently, quantum computing is limited because quantum computers are plagued by a wide variety of issues such as decoherence (the loss of the quantum nature of a particle) and often struggle to perform basic functions correctly. In normal computers, issues of poor computing can usually be solved by providing more storage to the computer, but this is currently not a feasible option for quantum computers. The unit of storage for quantum computing is a qubit (short for quantum bit) as opposed to a normal bit in standard computing. Researchers have to be highly conservative in their allocation of qubits, because unlike a typical computer which holds hundreds of billions of bits, the best quantum computers have around 50 qubits. Since the supply of information storage is in such scarce supply, researchers have been unable to find a way to divide qubits between error correction programs and the actual computation.^[6]

With the application of APM, researchers hope to able to build quantum computers with larger storage modules as well as components that can maintain a coherent state indefinitely. Once these limitations have been passed, quantum computers can begin to see commercial application.^[7]

Room Temperature Superconductors[]

A room temperature superconductor is a substance that possesses the property of superconductivity (electrical conduction with absolutely no resistive forces) at temperatures that could be considered room temperatures (above 0 °C).^[8] Room temperature superconductors have been a heavily sought technology due to the potential they hold to greatly increase energy efficiency.^[9] Usually, superconductors can only function in cryogenic environments and development on a room temperature superconductor has been unsuccessful until October 2020 when the first room temperature superconductive substance - made of carbon, hydrogen, and sulfur - was discovered.^[10][11]

However, this superconductor is still far from commercialization. It can only function at extremely high pressures comparable to that of the Earth's core.^[10] To create superconductors that can function at room temperatures and pressures, scientists are turning to APM to modify substances to behave differently.^[9]

Methods[]

Scanning Tunneling Microscope[]

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A current prospective method for fabricating atomically precise (AP) goods is under development at Zyvex Technologies where they plan to use a scanning tunneling microscope (STM) to move individual atoms. Typically, an STM is used to photograph atoms and molecules, but Zyvex has converted their STM's into machines with the required precision to position specific atoms. However, STM's are not efficient enough to be employed in large-scale manufacturing processes. Zyvex's current goal is to advance the design of STM's to the point where a large group of them can fabricate goods in industrial settings.^[12]

In order to have multiple scanning tunneling microscopes operating together, an extreme level of coordination and exactness is required. A major level of precision is provided by nanopositioners (stages that position microscope samples to accuracies of within a nanometer)^[13] which allow for exact positioning on the x, y, and z axes. Once the nanopositioners are ready, the manufacturing process can begin.^[12]

1. The first step in Zyvex's procedure is to construct a series of coordinated STM manufacturing devices that can work together efficiently and can handle the production a large volume of product.
2. Then a "feedback-controlled microelectromechanical system (MEMS)" will be implemented into the STM's that will allow them to operate independent of human supervision. The incorporation of the MEMS will allow the STM's to operate with anywhere from 100 to 1000 times more speed than before and with accuracy to within a nanometer, allowing for commercial usage.^[12]

Hydrogen Lithography[]

Hydrogen lithography is a method of APM revolving specifically around data storage. A team of researchers at the University of Alberta have used hydrogen lithography to store 1.2 petabits (150,000 gigabytes) worth of information into a one square inch area, making this form of data storage about 100 times more efficient than a Blu-Ray disc. The technology works by using an STM to move hydrogen atoms around on a silicon substrate to store information in binary as ones and zeroes. The presence of a hydrogen atom in a certain location signifies a one and the absence of a hydrogen atom in a certain location signifies a zero.^[14]

This technology represents a major leap forward from previous iterations of high density storage devices that only functioned under ultra-specific conditions such as at subzero temperatures or in a vacuum, making them highly impractical. The new storage method that uses hydrogen lithography is stable at room temperatures and at standard atmospheric pressure. The technology is also long-lasting, able to store information for more than half a century.^[14]

Hydrogen Depassivation Lithography[]

Hydrogen depassivation lithography (HDL) is a variant of electron beam lithography where the tip of a scanning tunneling microscope is modified to emit a cold field that fires a miniscule beam of electrons at surface covered with a film sensitive to electrons called a resist, typically made of silicon . The beam of electrons can then be manipulated to etch designs or patterns on the resist. HDL is performed in vacuums with temperatures ranging from subzero to around 250 °C. Currently, HDL can be carried out in one of two forms: up to five volts of power to create atomically precise patterns and an 8 volt mode with a wider area of effect. Once a design has been made, the result is developed through the process of desorption. Desorption is the opposite of absorption where a material separates from a surface instead of being enveloped by it.^[15] In HDL, the energy released when the electrons strike the surface of the silicon resist is enough to break the chemical bond between the silicon and hydrogen atoms and the hydrogen atom ends up being desorbed.^[16]

The five volt method has accuracy to distances of under a nanometer, but is relatively inefficient. A model that proves this method is atomically precise has been created shown as the formula

${\displaystyle i=KVe^{-2T_{d}{\sqrt {\left({\frac {2\phi m_{e}}{\hbar }}\right)}}}}$

where i is the value of the tunneling current in nA (nanoamperes), K is a constant equal to 0.194, V is the bias between the tip and the sample, e is Euler's number, ${\displaystyle T_{d}}$ is the size of the tunneling gap of the microscope, Φ is the height of the local barrier, ${\displaystyle m_{e}}$is the electron mass, and ${\displaystyle \hbar }$ is Planck's constant divided by ${\displaystyle 2\pi }$.^[16]

Criticisms and Controversies[]

A variety of concerns have been raised about the potential risks widespread APM could create.

Gray Goo[]

Some experts fear APM could contribute to the "gray goo" doomsday scenario wherein self-replicating molecular assemblers (machines that exist at the atomic scale) uncontrollably create copies of themselves, forming a gray goo that consumes the entire planet as a resource to continue replication. However, such a scenario would be extremely unrealistic. Not only would these molecular assemblers have to be purpose built for the function of creating gray goo, but developing these assemblers would take an extraordinary amount of resources to begin with. Assuming there even are people who would want to see the extinction of all life, they likely don't have the resources to see it through.^[5][17]

Economic[]

Another major issue with APM is the negative effect it could have on employment. By nature, APM is a very technologically complex medium and will require highly educated operators to be carried out. The concern is that if the economy shifts towards one that is heavily reliant on APM, the majority of the population will not have the necessary training to be successful and the poverty rate will rise.^[5]

Militarism[]

Many experts fear that APM could be used to develop novel, destructive weapons and spark another global Cold War. By making destructive weapons cheaper to develop, countries may be more likely engage in violence as well.^[5]

Surveillance and Privacy[]

A very realistic scenario would be one in which governments and security agencies use APM to manufacture tiny cameras and other spyware in order to spy on citizens. Many researchers have raised concerns about the infringement of rights that this type of technology could bring with it.^[5]

See also[]

• Drexler–Smalley debate on molecular nanotechnology
• Nanotechnology
• Molecular machine
• Molecular assembler

References[]