InGaAs/GaAs自组织量子点光致发光特性研究

摘要

Optical properties of InGaAs/GaAs self-organiz ed quantum dots (QDs) structures covered by InxGa1-xAs capping l ayers with different In contents x ranging from 0.0 (i.e., GaAs) to 0.3 were investigated systematically by photoluminescence (PL) measurements. Red-shift of the PL peak energies of the InAs QDs covered by InxGa1- xAs layers with narrower linewidth and less shifts of the PL emissions via variations of the measurement temperatures were observed compared with that cov ered by GaAs layers. Calculation and structural measurements confirm that the r ed-shift of the PL peaks are mainly due to strain reduction and suppression of the In/Ga intermixing due to the InxGa1-xAs cover layer, leading to better size uniformity and thus narrowing the PL linewidth of the QDs. 1.3μ m wavelength emission with very narrow linewidth of only 19.2 meV at room temper ature was successfully obtained from the In0.5Ga0.5As/GaAs QDs cover ed by the In0.2Ga0.8As layer.%用PL谱测试研究了GaAs和不同In组份InxGa1-xAs(x=0.1,0.2,0.3)覆盖层对分子束外延生长的InAs/GaAs自 组织量子点发光特性的影响.用InxGa1-xAs外延层覆盖InAs/GaAs量子点, 比用GaAs做覆盖层其发光峰能量向低能端移动,发光峰半高宽变窄,量子点发光峰能量随温度 的红移幅度变小.理论计算证实这是由于覆盖层InxGa1-xAs减小了InAs表 面应力导致发光峰红移,而In元素有效抑制了InAs/GaAs界面组份的混杂,量子点的均匀性得 到改善,PL谱半高宽变窄.用InGaAs覆盖的In0.5Ga0.5As/GaAs自组织量子点实 现了1.3μm发光,室温下PL谱半高宽为19.2meV,是目前最好的实验结果.