Removal of strain relaxation induced defects by flushing of InAs quantum dots
Removal of strain relaxation induced defects by flushing of InAs quantum dots
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DOI：
10.1088/0022-3727/45/36/365107
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发表时间：
2012-09
期刊：
影响因子：
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通讯作者：
V. Polojärvi;A. Schramm;A. Aho;A. Tukiainen;M. Guina
中科院分区：
文献类型：
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作者：
V. Polojärvi;A. Schramm;A. Aho;A. Tukiainen;M. Guina
我们报道了铟冲洗对GaAs肖特基二极管中应变弛豫InAs量子点的电学和光学性质的影响。InAs量子点有意地生长超过临界厚度以诱导塑性弛豫量子点。样品是用分子束外延方法在GaAs（100）衬底上连续和循环沉积InAs制备的。深能级瞬态谱（DLTS）的实验表明，广泛的位错引起的缺陷，在非冲洗样品。我们通过DLTS表明，量子点沉积后的铟冲洗显着减少量子点层中的电子陷阱的数量，并抑制到GaAs盖层的缺陷形成。使用电容-电压测量，我们观察到，冲洗的样品表现出在量子点状态的电子约束的恢复。此外，我们使用光致发光实验来分析直接与循环InAs沉积和铟冲洗步骤的影响。
We report the effect of indium flushing on the electrical and optical properties of strain-relaxed InAs quantum dots (QDs) embedded in GaAs Schottky diodes. The InAs QDs were intentionally grown beyond the critical thickness to induce plastically relaxed QDs. The samples were fabricated by molecular beam epitaxy on GaAs(1 0 0) substrates using continuous and cycled InAs deposition. Deep level transient spectroscopy (DLTS) experiments show broad dislocation-induced defects in non-flushed samples. We show by DLTS that indium flushing after QD deposition decreases remarkably the amount of electron traps in the QD layer and suppresses the defect formation into GaAs capping layer. Using capacitance–voltage measurements we observed that the flushed samples exhibit a recovery of electron confinement in the QD states. Furthermore, we used photoluminescence experiments to analyse the effects of direct versus cycled InAs deposition and indium flushing steps.