STRAINED SI1-XGEX SI DOTS AND WIRES GROWN BY SELECTIVE EPITAXY/

Selective epitaxial growth of Si1-xGex was studied with the aim to fab ricate quantum wires and dots. The selective deposition was performed by low pressure chemical vapor deposition with dichlorosilane and germ ane as precursors, at 0.1 Torr and 700 degrees C in a radiation heated , cold wall, high vacuum, quartz reactor. Dislocation free strained do ts and wires could be grown much thicker than the critical thickness f or unpatterned area, because the critical thickness by formation of mi sfit dislocations increases when the window dimension is reduced. For x up to 20% it was found that for 10x10 mu m(2) dots the critical thic kness increases by more than 4 times. The tendency of facet formation was exploited to realize laterally confined multiple quantum well dots and wires with sizes down to 50 nm. Besides the emission from the (10 0) quantum well layers excitonic emissions from quantum well layers fr om flat {110} facets and from islands in the (100) and {311} facets we re detected. All dots and wires luminesce stronly down to the lowest a chieved dimension of 50 nm, the integral intensity exceeding that from the substrate.