High-Indium-content nonpolar quantum wells for green, yellow, and red light emitters

目前，缺乏对偏振场的控制是限制III-氮化物基异质结在包括绿色激光二极管在内的绿色和更长波长发光器件中应用的主要因素。通过利用非极性取向来控制偏振场，我们旨在为更好的可见光发射器打开大门。非极性异质结的外延生长将被研究和优化，以获得低缺陷密度、陡峭的界面和均匀的成分。重点放在适合绿色和更长波长应用的高铟含量的GaInN量子阱上。作为一个关键，In的掺杂率超过30%需要控制，以保持完全的晶格匹配以及完全均匀和化学计量的生长。时间分辨光学光谱和光学增益光谱揭示了非辐射复合损失的影响，包括缺陷和本征复合。通过共振光电流噪声光谱获得有关缺陷能级的直接信息。在与研究小组合作伙伴的协作下，将把非极方法与半极方法和极地方法进行比较。

The lack of control of polarization fields is presently a major factor limiting application of III-nitride based heterostructures for green and longer wavelength light-emitting devices, including green laser diodes.By controlling polarization fields through the use of non-polar orientations we aim at opening the door for better visible light emitters. Epitaxial growth of non-polar heterostructures will be studied and optimized for low defect densities, abrupt interfaces and homogeneous compositions. The emphasis is on GaInN quantum wells with high Indium content suited for green and longer wavelength applications. As a key, Indium incorporation beyond 30% needs to be controlled maintaining full lattice-matching as well as fully homogeneous and stochiometric growth.Time-resolved optical spectroscopy as well as optical gain spectroscopy reveal the influence of nonradiative recombination losses, both due to defects and to intrinsic recombination. Direct information about defect levels is obtained through resonant photocurrent noise spectroscopy. In collaboration with partners from the Research Group, the non-polar approach will be compared to the semipolar and the polar approach.