GaN quantum structures with fractional dimension -from quantum well to quantum dot

GaN quantum structures with various fractional dimensions were fabricated on Al_xGa_1-xN surfaces. The Al_xGa_1-xN surface was treated with a Si antisurfactant prior to the GaN deposition. This treatment was found to be effective in modifying the structural dimensions of the thin GaN layer. Without Si a GaN quantum well structure having a dimensionality of two was achieved in step flow growth mode. As the deposited amount of Si was increased, a morphological transition from quantum well (2D) to quantum dot (0D-like) occurred. At some Si doses the resulting structures possessed fractional dimensions. We observed that GaN quantum structures with various fractional dimensions could be controllably fabricated solely by varying the total amount of the deposited Si antisurfactant. A model concerning masking by Si-N bondings is introduced to explain the morphological transitions.