Cooperative Phenomena on Grass Transition of Amorphous Semiconductors -Hierarchical Energy Distribution and Fractal Structure-

各种硫系非晶半导体(As_2S_3，As_xSe_&lt；1-x&gt；(0*x*0.4)，(As_2S_3)_&lt；100-x&gt；Agx(0*x*6)，(GeS_2)_&lt；1-x&gt；(Sb_2S_3)_x(x*0.33)，Ge_xS_&lt；1-x&gt；(Sb_2S_3)_x(x*0.33)，Ge_xS_&lt；1-x&gt；(0.07*x*0.37)，用差示扫描量热法测定了沸石的热容数据。热容曲线的分析采用Moynihan公式，其松弛函数为kww为phi(T)-exp[-(t/tau)^&lt；beta&gt；]。研究发现，非指数β随退火虚拟温度的降低而线性减小，组态约束随退火温度的升高而增加，从而使结构弛豫变得更加协调。这一观察结果可以用分层的能量图景来理解，这表明能垒的分层分布是理解结构弛豫动力学的重要方面之一。对K…的分析对不同维度和局域结构的各种非晶态半导体的玻璃化转变结构松弛的更多WW行为表明，KWW行为强烈地依赖于底层几何结构(如维度、各向异性、分形)。我们还发现，在沸石分子筛中掺入Se后，a-Se的玻璃化转变温度和玻璃化转变活化能都发生了显著的变化。它们强烈地依赖于孔的大小(沸石的窗口直径)。结果表明，a-Se玻璃化转变过程中的结构弛豫动力学受分子筛中的几何限制和不存在团簇间相互作用的影响。将分形子模型应用于低温拉曼光谱得到的非类德拜振动激发，测定了Ge_xS_&lt；1-x&gt；体系的分维，发现玻璃转变结构弛豫的非指数β与分维密切相关。这证明了玻璃化转变的动力学(过冷液体的结构松弛)决定了玻璃化结构的静态模式。较少

The structural relaxation in the glass transition for various chalcogenide amorphous semiconductors (As_2S_3, As_xSe_<1-x> (0*x*0.4), (As_2S_3) _<100-x>Ag_x (0*x*6), (GeS_2) _<1-x> (Sb_2S_3) _x (x*0.33), Ge_xS_<1-x> (0.07*x*0.37), Se loaded into zeolites) has been investigated with the heat capacity data obtained on differential scanning calorimetry experiments. The heat capacity curves were analyzed by the Moynihan formulation with a KWW relaxation function phi (t) -exp [- (t/tau) ^<beta>]. It has been found that the nonexponentiality beta decreases linearly with a decrease in fictive temperature during annealing, and the configurational constraints increase with annealing so that the structural relaxation becomes more cooperative. The observation can be understood in terms of a hierarchical energy landscape, suggesting that the hierarchical distribution of energy barriers is one of important aspects for the understanding of the dynamics of the structural relaxation. Analyzes of the K … More WW-behavior on the structural relaxation of glass transition for various amorphous semiconductors with different dimensionality and local structures suggest that the KWW-behavior depends strongly on the underlying geometry (e.g.dimensionality, anisotropy, fractal). We have also found that the glass transition temperature and the activation energy for the glass transition of a-Se are remarkably modified when Se is incorporated in zeolites. They depends strongly on the pore size (window diameter of zeolites). The result implies that the dynamics of the structural relaxation in the glass transition of a-Se is significantly influenced by the geometrical restriction in the zeolites and by the absence of inter-cluster interaction. We determined fractal dimensions for Ge_xS_<1-x> system by applying a fracton model to the non-Debye-like vibrational excitation obtained from the low temperature low frequency Raman spectra, and found that the nonexponentiality beta of the structural relaxation of glass transition is strongly correlated with the fractal dimension. This is the evidence that the dynamics of glass transition (structural relaxation of supercooled liquid) rules over the static pattern of glassy structure. Less