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AlGaN/GaN HEMT结构材料主要用于研制微电子器件,对其发光性质的研究相对较少。通过对AlGaN/GaN HEMT结构材料的光致发光谱(PL)研究,观测到了AlGaN势垒层中Al组分为40%的AlGaN/AlN/GaN结构中二维电子气(2DEG)光致发光及其能级分裂现象。在4.5 K低温下,其2DEG发光峰在GaN带边峰能量以下30和40 meV处分裂成两个峰位,直至温度持续升高至40 K后消失。根据GaN价带顶部在单轴晶格场和自旋-轨道耦合共同作用下的能级分裂理论,因自旋-轨道耦合引起的2DEG发光峰两个分裂能级差约为10 meV,与实验测得的结果一致,因此实验观测到的2DEG发光峰的分裂现象是由于氮化镓价带能级的自旋-轨道耦合而形成的。
AlGaN / GaN HEMT structure material is mainly used for the development of microelectronic devices, the study of its light-emitting properties is relatively small. Through the study of photoluminescence (PL) of AlGaN / GaN HEMT materials, two-dimensional electron gas (2DEG) photoluminescence of AlGaN / AlN / GaN with Al composition of 40% Its energy level split. At a low temperature of 4.5 K, the 2DEG luminescence peak cleaved into two peaks at 30 and 40 meV below the peak energy of the GaN band, and disappeared until the temperature reached 40 K. According to the theory of energy level splitting at the top of GaN valence band under the combination of uniaxial lattice field and spin-orbit coupling, the difference of 2DEG of 2DEG luminescence peak due to spin-orbit coupling is about 10 meV, The experimental results show that the splitting of the 2DEG luminescence peak observed experimentally is due to the spin-orbit coupling of the gallium nitride valence band energy level.