LEED studies of vicinal surfaces of germanium

Clean germanium surfaces inclined at small angles to (111), (100) and (110) planes were investigated by LEED. Surfaces with orientations close to (111) and (100) are stepped and regular steps are retained in the whole temperature range investigated.Steps with (111) terraces and edges towards $\text{2}\text{1}\text{1}\text{]}$ have a height of about one interplanar distance d₁₁₁ at all temperatures, and steps with edges towards $\text{2}\text{11]}$ have a height of about two interplanar distances below 500°C and of about one interplanar distance above 500°C. Steps with (100) terraces and edges in the 011] direction have a height about two interplanar distances d₁₀₀. The surfaces with orientations close to (110) are facetted at room temperature. The (17 15 1) facets are present on the surfaces oriented in the $\text{1}\text{10]}$ zone and the (10 9 2) facets on the surfaces oriented in the 001] zone. At high temperatures (about 480 and 770°C respectively) a reversible structural reconstruction of these surfaces into stepped ones takes place.