Semiconductors are considered by many technologists as the basis of more efficient electronic devices, especially those designed to deliver and convert power. A semiconductor is a substance, such as a solid chemical element or compound, that can conduct electricity under one set of conditions but another. This enables the semiconductor to control electrical current. Compounds of silicon or gallium are the most widely used in electronic devices.
Semiconductors are found at the heart of microprocessor chips as well as in transistors. Generally, anything that is computerized or uses radio waves depends on semiconductors.
New research, focused on improving semi-conductors, is looking at single crystals of diamonds. Researchers, such as Zhengqiang Ma from the University of Wisconsin-Madison, are of the view that diamonds could make the perfect semiconductors. Diamonds are thermally conductive (in that they dissipate heat quickly avoiding the need for expensive methods for cooling.) Furthermore, diamonds can handle high voltages and power. This means electrical currents flow through diamonds quickly, leading to good energy efficiency.
The stumbling block is with “doping” the diamonds. This refers to a process whereby other elements are integrated into the semiconductor to change its properties. The structure, and hardness, of the diamonds makes this difficult.
Professor Ma has pioneered a technique whereby diamonds. This involves coating diamonds with boron at relatively low temperatures. Professor Ma’s process is more effective than earlier attempts, whereby diamonds are coated with boron and heated to 1450 degrees Celsius. This carries the risk of creating crystals that are irregular in shape and more inefficient.
The new process involves bonding a single-crystal diamond with a piece of silicon doped with boron, at 800 degrees Celsius. This enables the boron atoms to migrate from the silicon to the diamond, which does not result in structural problems. This has been termed “selective p-type doping.”
The findings are published in the Journal of Applied Physics. The research paper is titled “Thermal diffusion boron doping of single-crystal natural diamond.”
