Tong C Z, Yoon S F
School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798, Republic of Singapore.
Nanotechnology. 2008 Sep 10;19(36):365604. doi: 10.1088/0957-4484/19/36/365604. Epub 2008 Jul 28.
We have directly imaged the formation of a GaAs quantum ring (QR) using droplet epitaxy followed by annealing in arsenic ambient. Based on the atomic force micrograph measurement and the analysis of surface energy, we determine that the formation of self-assembled GaAs QRs is due to the gallium atom's diffusion and crystallization driven by the gradient of surface energy. The phenomenon that GaAs is etched by the gallium droplets is reported and analyzed. It has been demonstrated that the epitaxy layers, such as AlAs and InGaP, can be used as the etching stop layer and hence can be used to control the shape and height of the QRs.
我们利用液滴外延法，随后在砷环境中进行退火处理，直接成像了砷化镓量子环（QR）的形成过程。基于原子力显微镜测量和表面能分析，我们确定自组装砷化镓量子环的形成是由于表面能梯度驱动的镓原子扩散和结晶。报道并分析了砷化镓被镓液滴蚀刻的现象。已经证明，诸如砷化铝和磷化铟镓等外延层可以用作蚀刻停止层，因此可用于控制量子环的形状和高度。
