An article on the Technology Research News website ("Nanotube array could form chips", by Ted Smalley Bowen) describes work by a group of researcers from the Samsung Advanced Institute of Technology and the Chonbuk National University in Korea who have made nanotube field-effect transistors in bulk by a relatively crude process that involves growing them in vertical bunches, then using electron beam lithography and ion etching to make the source, gate and drain electrodes that control the flow of electrons. Their carbon nanotube transistors worked at temperatures up to an extremely cold -243 degrees Celsius. The report dryly notes that the transistors will need to work at much warmer temperatures to be used in practical devices, and includes comments from other nanotube researchers to the effect that the researchers' method is still very rough, and they did not demonstrate that individual transistors could be accessed. The nanotubes rough composition limits their use, said Yue Wu, associate professor of physics at the University of North Carolina. "The carbon nanotubes are very defective. The device won't work at room temperature because the tubes are not clean semiconductors," he said. The work was reported in the 26 November 2001 issue of Applied Physics Letters.