Czelej Kamil, Mansoor Mubashir, Sarsil Mehmet Ali, Tas Mert, Sorkhe Yahya A, Mansoor Mehya, Mansoor Maryam, Derin Bora, Ergen Onur, Timur Servet, Ürgen Mustafa
Faculty of Chemical and Process Engineering, Warsaw University of Technology, Waryńskiego 1, 00-645 Warsaw, Poland.
Department of Complex System Modeling, Institute of Theoretical Physics, Faculty of Physics, University of Warsaw, Ludwika Pasteura 5, 02-093 Warsaw, Poland.
Chem Mater. 2024 Jun 19;36(13):6392-6409. doi: 10.1021/acs.chemmater.4c00178. eCollection 2024 Jul 9.
GaN is a technologically indispensable material for various optoelectronic properties, mainly due to the dopant-induced or native atomic-scale point defects that can create single photon emitters, a range of luminescence bands, and n- or p-type conductivities. Among the various dopants, chromium and manganese-induced defects have been of particular interest over the past few years, because some of them contribute to our present-day light-emitting diode (LED) and spintronic technologies. However, the nature of such atomistic centers in Cr and Mn-doped GaN is yet to be understood. A comprehensive defect thermodynamic analysis of Cr- and Mn-induced defects is essential for their engineering in GaN crystals because by mapping out the defect stabilities as a function of crystal growth parameters, we can maximize the concentration of the target point defects. We therefore investigate chromium and manganese-induced defects in GaN with methods using the highly accurate exchange-correlation hybrid functionals, and the phase transformations upon excess incorporation of these dopants using the CALPHAD method. We also investigate the impact of oxygen codoping that can be unintentionally incorporated during crystal growth. Our analysis sheds light on the atomistic cause of the unintentional n-type conductivity in GaN, being O-related. In the case of Cr doping, the formation of Cr defects is the most dominant, with an charge transition at + 2.19 eV. Increasing nitrogen partial pressure tends to enhance the concentration of Cr. However, in the case of doping with Mn, several different Mn-related centers can form depending on the growth conditions, with Mn being the most dominant. Mn possesses the , , and charge transitions at 0.56, 1.04, and 2.10 eV above the VBM. The incorporation of oxygen tends to cause the formation of the Mn-V center, which explains a series of prior experimental observations in Mn-doped GaN. We provide a powerful tool for point defect engineering in wide band gap binary semiconductors that can be readily used to design optimal crystal growth protocols.
氮化镓由于其掺杂诱导或本征原子尺度点缺陷能够产生单光子发射体、一系列发光带以及n型或p型导电性，因而成为各种光电器件中技术上不可或缺的材料。在各种掺杂剂中，铬和锰诱导的缺陷在过去几年中备受关注，因为其中一些对当今的发光二极管（LED）和自旋电子技术有重要作用。然而，Cr和Mn掺杂的GaN中此类原子中心的性质尚不清楚。对Cr和Mn诱导的缺陷进行全面的缺陷热力学分析对于它们在GaN晶体中的工程应用至关重要，因为通过绘制缺陷稳定性随晶体生长参数的变化关系，我们可以最大化目标点缺陷的浓度。因此，我们使用高精度交换关联混合泛函方法研究了GaN中铬和锰诱导的缺陷，并使用CALPHAD方法研究了这些掺杂剂过量掺入时的相变。我们还研究了晶体生长过程中可能无意掺入的氧共掺杂的影响。我们的分析揭示了GaN中无意n型导电性与氧相关的原子原因。在Cr掺杂的情况下，Cr缺陷的形成最为主要，其电荷跃迁为 + 2.19 eV。增加氮分压往往会提高Cr的浓度。然而，在Mn掺杂的情况下，根据生长条件会形成几种不同的Mn相关中心，其中Mn中心最为主要。Mn在价带顶上方0.56、1.04和2.10 eV处具有 、 和 电荷跃迁。氧的掺入倾向于导致Mn - V中心的形成，这解释了Mn掺杂GaN中一系列先前的实验观察结果。我们为宽带隙二元半导体中的点缺陷工程提供了一个强大的工具，可用于设计最佳的晶体生长方案。
