FIELD-EFFECT ON THERMAL EMISSION FROM THE 0.40 EV ELECTRON LEVEL IN INGAP

Results are reported of electric-field dependence on thermal emission of electrons from the 0.40 eV level at various temperatures in InGaP by means of deep-level transient spectroscopy. The data are analyzed according to the Poole-Frankel emission from the potentials which are assumed to be Coulombic, square well, and Gaussian, respectively. The emission mte from this level is strongly field dependent. It is found that the Gaussian potential model is more reasonable to describe the phosphorus-vacancy-induced potential in InGaP than the Coulombic and square-well ones.

GaAs中过渡族杂质Pd和Zr有关的深中心

采用结谱、光荧光等技术对Pd和Zt在GaAs中的光学和电学性质进行了研究.在GaAs:Pd中观测到三个能级,分别位于导带下0.4eV、0.60eV和价带上0.69eV.在GaAs:Zr中也观测到三个能级,分别位于导带下0.43eV和介带上0.32eV和0.55eV.基于深中心所表现出的Poole-Frenkel效应,讨论了一些中心对应的荷电态,对它们的俘获和对光致发光的影响也作了研究,结果表明:Pd和Zr在GaAs中均不是有效的复合中心.

Performance improvement by charge trapping of doping fluorescent dyes in organic memory devices

We studied the memory effect in the devices consisting of dye-doped N, N'-di(naphthalene-1-yl)-N, N'-diphenyl-benzidine sandwiched between indium-tin oxide and Ag electrodes. It was found that the on/off current ratio was greatly improved by the doped fluorescent dyes compared with nondoping devices. A mechanism of charge trapping was demonstrated to explain the improvement of the memory effect. For the off state, the conduction process is dominated by the trapping current, which is a characteristic of the space-charge limited current, whereas the on state is dominated by the detrapping current, and interpreted by Poole-Frenkel emission.