Light-Emitting Mechanism of Rare-Earth Doped III-V Compound Semiconductor and the Light-Emitting Devices of Carrier Injection Type

研究了稀土掺杂III-V化合物半导体和Si的光致发光（PL）和电致发光（EL）光谱，以明确液相外延（LPE）、热扩散和离子注入三种方法制备的样品的发光机理。我们观察到与稀土原子内部4f-4f跃迁有关的特殊峰（与半导体的光学性质或能带结构无关）的发光光谱。稀土掺杂III-V化合物半导体体系是一种很有前途的新型光电子器件和EL器件，如激光二极管和发光二极管。得到了以下结果液相外延（LPE）通过对不同的Yb化合物如YbF_3，YbP在GaAs中进行PL或EL测量，获得了Yb^<3+>在1000nm左右的相关发光。对于EL样品，GaAs中的稀土可以通过注入载流子激发。与InP: YbCl_3相比，GaAs: YbP和GaAs: YbP的Yb^<3+>相关发射相对较宽，这是因为Yb^<3+>在GaAs中形成了复杂的中心，带有一些缺陷或杂质Si中的Er^<3+>离子产生1540nm左右的Er^<3+>相关发光，其光致发光激发光谱（PLE）由Er^<3+>离子直接激发产生的尖峰组成。对于InP: Er，未观察到Er^<3+>相关发光离子注入inp: Yb和Si；与LPE相比，Er表现出强烈的稀土相关发射和热扩散。对于InP: Yb，当Yb^<3+>离子被InP带隙以下的光子能量激发时，Yb^<3+>相关发射较强，这是因为通过缺陷能级发生了向Yb^<3+>离子的新的有效能量转移过程。

Photoluminescence (PL) and electroluminescence (EL) spectra of rare earth doped III-V compound semiconductors and Si were investigated in order to clear the light emitting mechanism of the samples prepared by three methods such as liquid-phase epitaxy (LPE), thermal diffusion and ion-implantaion. We observed the luminescence spectra with peculiar peaks which are related to the internal 4f-4f transitions of the rare earth atoms, (which are independent of the optical properties or the band structure of semiconductor). The rare earth doped III-V compound semiconductor systems are promising materials for a new type of optoelectronic devices and EL devices such as laser diode and light-emitting diode. The following results were obtained.1 Liquid-phase epitaxy (LPE)The Yb^<3+>-related luminescence around 1000nm was obtained through the PL or EL measurements from different Yb compounds as YbF_3,YbP in GaAs.For EL samples, the rare earth in GaAs can be excited by carrier injection.The Yb^<3+>-related emission of GaAs : YbF_3 and GaAs : YbP was relatively broad compared with InP : YbCl_3 because the Yb^<3+> forms complex centers with some defects or impurities in GaAs.2 Thermal diffusionThe Er^<3+>-related luminescence around 1540nm was obtained from the Er^<3+>ions in Si, and the photoluminescence excitation spectroscopy (PLE) spectra consisted of sharp peaks which were caused by the direct excitation of Er^<3+>ions.For InP : Er, Er^<3+>-related luminescence was not observed.3 Ion-implantationInP : Yb and Si ; Er showed intense rare-earth related emission compared with LPE and a thermal diffusion.For InP : Yb, when Yb^<3+>ion was excited by the photon energy below the InP-band-gap, Yb^<3+>-related emssion was strong because the new efficient energy transfer processes to Yb^<3+> ions occurred through the defect energy levels.