Christian George, Kappers Menno, Massabuau Fabien, Humphreys Colin, Oliver Rachel, Dawson Philip
School of Physics and Astronomy, Photon Science Institute, University of Manchester, Manchester M13 9PL, UK.
Department of Materials Science and Metallurgy, University of Cambridge, Cambridge CB3 0FS, UK.
Materials (Basel). 2018 Sep 15;11(9):1736. doi: 10.3390/ma11091736.
In this paper we report on the optical properties of a series of InGaN polar quantum well structures where the number of wells was 1, 3, 5, 7, 10 and 15 and which were grown with the inclusion of an InGaN Si-doped underlayer. When the number of quantum wells is low then the room temperature internal quantum efficiency can be dominated by thermionic emission from the wells. This can occur because the radiative recombination rate in InGaN polar quantum wells can be low due to the built-in electric field across the quantum well which allows the thermionic emission process to compete effectively at room temperature limiting the internal quantum efficiency. In the structures that we discuss here, the radiative recombination rate is increased due to the effects of the Si-doped underlayer which reduces the electric field across the quantum wells. This results in the effect of thermionic emission being largely eliminated to such an extent that the internal quantum efficiency at room temperature is independent of the number of quantum wells.
在本文中，我们报告了一系列InGaN极性量子阱结构的光学性质，这些量子阱的数量分别为1、3、5、7、10和15，并且在生长过程中包含一个InGaN Si掺杂底层。当量子阱数量较少时，室温下的内量子效率可能由量子阱的热电子发射主导。这种情况可能发生，是因为InGaN极性量子阱中的辐射复合率可能较低，这是由于量子阱上的内建电场导致的，该电场使得热电子发射过程在室温下能够有效竞争，从而限制了内量子效率。在我们这里讨论的结构中，由于Si掺杂底层的作用，辐射复合率增加，这降低了量子阱上的电场。这导致热电子发射的影响在很大程度上被消除，以至于室温下的内量子效率与量子阱的数量无关。
