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

研究了稀土掺杂的III-V化合物半导体和Si的光致发光(PL)和电致发光(EL)光谱，以阐明用液相外延(LPE)、热扩散和离子注入三种方法制备的样品的发光机理。我们观察到了与稀土原子内部4f-4f跃迁有关的特殊峰的发光光谱(与半导体的光学性质或能带结构无关)。稀土掺杂的III-V化合物半导体系统是一种很有前途的新型光电子器件和电致发光器件如激光二极管和发光二极管的材料。1.液相外延(LPE)通过测量不同Yb化合物如YbF_3、YbP在GaAs中的发光或电致发光，获得了约1000 nm的与Yb^&lt；3&gt；有关的发光。对于EL样品，可以通过载流子注入激发出GaAs中的稀土。与InP：YbCl_3相比，与Yb^&lt；3&gt；有关的发射相对较宽，这是因为Yb^&lt；3&gt；在GaAs中形成了具有某些缺陷或杂质的复杂中心。2热扩散InP：Yb和Si；Er离子在1540 nm附近发光，光致发光激发光谱(PLE)光谱由Er^&lt；3和Gt；离子直接激发产生的尖峰组成。对于InP：InP：Yb和Si；Er离子在InP：Yb和Si；Er中表现出强烈的稀土相关发光，当Yb和Si；Er被InP带隙以下的光子能量激发时，Yb&gt；离子被InP带隙以下的光子激发时，Yb&gt；3&gt；相关发射很强，因为新的有效能量转移过程是通过缺陷能级向Yb^&lt；3&gt；离子转移的。

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.