The electric characteristics of Ge quantum dot grown by molecular beam epitaxy in Si matrix were investigated by admittance spectroscopy and deep level transient spectroscopy. The admittance spectroscopy measurements ...The electric characteristics of Ge quantum dot grown by molecular beam epitaxy in Si matrix were investigated by admittance spectroscopy and deep level transient spectroscopy. The admittance spectroscopy measurements show that the activation energy of 0.341eV can be considered as the emitting energy of hole from the ground state of the quantum dot. And the capacitance variation with temperature of the sample shows a platform at various frequencies with reverse bias (0.5 V,) which indicates that the boundary of space charge region is located at the quantum dot layer where the large confined hole concentration blocks the further extension of space charge region. When the temperature increases from 120K to 200K, the holes in the dot emit out completely. The position of the platform shifting with the increase of the applied frequency shows the frequency effects of the charges in the quantum dot. The deep level transient spectroscopy results show that the charge concentration in the Ge quantum dot is a function of the pulse duration and the reverse bias voltage, the activation energy and capture cross-section of hole decrease with the increase of pulse duration due to the Coulomb charging effect. The valence-band offsets of hole in Ge dot obtained by admittance spectroscopy and deep level transient spectroscopy are 0.341 and 0.338eV, respectively.展开更多
This paper constructs a new spectrum of networks by means of the matrix of link-state ofthe network,which can reveal the characteristics of the correlation between the degrees of the network.Also,the computation of th...This paper constructs a new spectrum of networks by means of the matrix of link-state ofthe network,which can reveal the characteristics of the correlation between the degrees of the network.Also,the computation of this spectrum of networks is usually more feasible and more efficient due tothe much lower order of its matrix of link-state than its adjacent matrix in practice.Some estimatesfor the bounds of the key eigenvalues in the spectrum are obtained,the corresponding inequalities arepresented and proved.For the sake of its application,the authors define spectrum of networks in twoways,and all theorems are given in parallel for both kinds of definition.In addition,the authors finda symmetry in the spectrum,which is relative to the characteristic of structure of its network to someextent.展开更多
基金Project(60276025) supported by the National Natural Science Foundation of China
文摘The electric characteristics of Ge quantum dot grown by molecular beam epitaxy in Si matrix were investigated by admittance spectroscopy and deep level transient spectroscopy. The admittance spectroscopy measurements show that the activation energy of 0.341eV can be considered as the emitting energy of hole from the ground state of the quantum dot. And the capacitance variation with temperature of the sample shows a platform at various frequencies with reverse bias (0.5 V,) which indicates that the boundary of space charge region is located at the quantum dot layer where the large confined hole concentration blocks the further extension of space charge region. When the temperature increases from 120K to 200K, the holes in the dot emit out completely. The position of the platform shifting with the increase of the applied frequency shows the frequency effects of the charges in the quantum dot. The deep level transient spectroscopy results show that the charge concentration in the Ge quantum dot is a function of the pulse duration and the reverse bias voltage, the activation energy and capture cross-section of hole decrease with the increase of pulse duration due to the Coulomb charging effect. The valence-band offsets of hole in Ge dot obtained by admittance spectroscopy and deep level transient spectroscopy are 0.341 and 0.338eV, respectively.
基金supported by the Key Project for Fundamental Research of STCSM under Grant No. 06JC14057
文摘This paper constructs a new spectrum of networks by means of the matrix of link-state ofthe network,which can reveal the characteristics of the correlation between the degrees of the network.Also,the computation of this spectrum of networks is usually more feasible and more efficient due tothe much lower order of its matrix of link-state than its adjacent matrix in practice.Some estimatesfor the bounds of the key eigenvalues in the spectrum are obtained,the corresponding inequalities arepresented and proved.For the sake of its application,the authors define spectrum of networks in twoways,and all theorems are given in parallel for both kinds of definition.In addition,the authors finda symmetry in the spectrum,which is relative to the characteristic of structure of its network to someextent.
