Investigation of Si(111)- (7x7) surface at different temperatures with STM

In this work, by means of Scanning Tunneling Microscopy ( STM) we studiedthe surface evolution of Si (111) 7x7 at different temperatures (25◦C, -155◦C ve327◦C) . We used tungsten electrochemically etched tips. The sample was heatedby passing a dc electric current through it, and cleaned by flashing at 1250 ºC2x 10 −10 mbar. We measured the sample high temperature with anbelowinfirared pyrometer. Si(111)-(7x7) reconstructured surface was prepared bydirect current heating. The STM results are compared with the experimentalfindings.