Surfaces of silicon

The author reviews the current state of knowledge of the structure and surface states of several clean low-index faces of silicon. These are the (100) face, the (111) 7*7 face, the (111) 1*1 face and the (111) 2*1 cleavage face. A new model for the latter is also proposed. Aided particularly by scanning tunneling microscopy results there appears to be grounds for some confidence that the structures of most of the above reconstructed surfaces are now understood. In addition to reviewing results from a variety of experimental techniques used on clean surfaces, results for gas covered and metal covered surfaces are also summarised.