Fe掺杂GaN晶体非极性面的光学各向异性研究

本文利用低温光致发光谱(PL)研究了Fe掺杂GaN晶体非极性a面{1120}、m面{1100} 的带边峰和Fe³⁺相关峰(⁴T₁(G)- ⁶A₁(S))的偏振发光特性。结果表明:a面与m面光学各向异性差别较小,线偏振光的电矢量E平行于c轴[0001]时(E∥c),GaN带边峰强度最小,而Fe³⁺零声子峰(1.299 eV)强度最强。带边峰线偏振度小,而Fe³⁺零声子峰线偏振度大,a面带边峰的线偏振度为26％,Fe³⁺零声子峰的偏振度在a面和m面分别达到55%和58%。在5 K低温下,进一步测量了Fe³⁺精细峰和声子伴线的偏振特性,结果表明,除了一个微弱的峰外,其他精细峰和声子伴线与Fe³⁺零声子峰偏振特性一致。本研究有助于拓展Fe掺杂GaN晶体材料在新型偏振光电器件领域的应用。

Optical Anisotropy of Non-Polar Surfaces of Fe-Doped GaN Crystal

In this paper, the polarization luminescence characteristics of the near-band-edge peak and Fe³⁺ related emission peaks(⁴T₁(G)-⁶A₁(S)) of the non-polar surfaces including a-plane {1120} and m-plane {1100} of Fe-doped GaN crystal were studied by low-temperature photoluminescence(PL) measurement. The results show that the optical anisotropy of a-plane and m-plane are similar. When the linearly polarized electric-field vector E is parallel to the c-direction [0001] (E//c), the intensity of GaN near-band-edge peak is the lowest, and the intensity of Fe³⁺ zero-phonon line (1.299 eV) is the strongest. The degree of polarization of Fe³⁺ zero-phonon line is greater than that of near-band-edge peak. The degree of polarization of near-band-edge peak of a-plane is 26%, while the degree of polarization of Fe³⁺ zero-phonon line reaches up to 55% and 58% of a-plane and m-plane GaN, respectively. The polarization characteristics of Fe³⁺ fine peak and the additional lines are further measured at 5 K. The results show that, except for one weak peak, other peaks are consistent with the polarization characteristics of Fe³⁺ zero-phonon line. This study is helpful to expand the application of Fe-doped GaN crystal in the field of novel optical and electrical devices.