Ščajev Patrik, Prystawko Paweł, Kucharski Robert, Kašalynas Irmantas
Institute of Photonics and Nanotechnology, Faculty of Physics, Vilnius University, Saulėtekio Ave. 3, 10257 Vilnius, Lithuania.
Laboratory of Semiconductor Characterization, Institute of High Pressure Physics PAS (UNIPRESS), ul. Sokołowska 29/37, 01-142 Warsaw, Poland.
Materials (Basel). 2024 Dec 7;17(23):5995. doi: 10.3390/ma17235995.
We investigated the carrier dynamics of ammonothermal Mn-compensated gallium nitride (GaN:Mn) semiconductors by using sub-bandgap and above-bandgap photo-excitation in a photoluminescence analysis and pump-probe measurements. The contactless probing methods elucidated their versatility for the complex analysis of defects in GaN:Mn crystals. The impurities of Mn were found to show photoconductivity and absorption bands starting at the 700 nm wavelength threshold and a broad peak located at 800 nm. Here, we determined the impact of Mn-induced states and Mg acceptors on the relaxation rates of charge carriers in GaN:Mn based on a photoluminescence analysis and pump-probe measurements. The electrons in the conduction band tails were found to be responsible for both the photoconductivity and yellow luminescence decays. The slower red luminescence and pump-probe decays were dominated by Mg acceptors. After photo-excitation, the electrons and holes were quickly thermalized to the conduction band tails and Mg acceptors, respectively. The yellow photoluminescence decays exhibited a 1 ns decay time at low laser excitations, whereas, at the highest ones, it increased up to 7 ns due to the saturation of the nonradiative defects, resembling the photoconductivity lifetime dependence. The fast photo-carrier decay time observed in ammonothermal GaN:Mn is of critical importance in high-frequency and high-voltage device applications.
我们通过在光致发光分析和泵浦-探测测量中使用带隙以下和带隙以上的光激发，研究了氨热法制备的锰补偿氮化镓（GaN:Mn）半导体的载流子动力学。非接触式探测方法阐明了它们在GaN:Mn晶体缺陷复杂分析中的通用性。发现锰杂质表现出光电导性和吸收带，起始波长阈值为700 nm，在800 nm处有一个宽峰。在此，我们基于光致发光分析和泵浦-探测测量，确定了锰诱导态和镁受主对GaN:Mn中载流子弛豫速率的影响。发现导带尾部的电子对光电导性和黄色发光衰减都有贡献。较慢的红色发光和泵浦-探测衰减由镁受主主导。光激发后，电子和空穴分别迅速热化到导带尾部和镁受主。黄色光致发光衰减在低激光激发下表现出1 ns的衰减时间，而在最高激发下，由于非辐射缺陷的饱和，它增加到7 ns，类似于光电导寿命的依赖性。在氨热法制备的GaN:Mn中观察到的快速光载流子衰减时间在高频和高压器件应用中至关重要。
