 In 2013, a carbon nanotube (CNT) thin yarn thermoacoustic earphone together with CNT thin yarn thermoacoustic chip was demonstrated by a research group of Tsinghua-Foxconn Nanotechnology Research Center in Tsinghua University, using a Si-based semi-conducting technology compatible fabrication process.Near-term commercial uses include replacing piezoelectric speakers in greeting cards.AIST nanotech 2009 .