n^+-i-n^+结构的电极附近结区电场对SCLC法确定薄a—Si:H膜隙态密度的影响──计算机模拟分析

Effect of Electric Field at Junction Region in n^+-i-n^+ Devices on the Determination of the Density of States in Thin a-Si:H Films by Space-Charge-Limited-Current Technique──A Computer Simulation

将描述电极性质的结区电场选作n^+-i-n^+或(n^+-n-n^+)结构a—Si:H器件电流流动微分方程组的另一对边界条件,应用Runge-Kutta法由初值问题技术解微分方程组得到该器件J-V特性数值解。在此基础上,空间电荷限制电流(SCLC)法推导出不同厚度薄a—Si:H样品隙态密度,证实了其费米能级附近隙态密度G(E_F)随厚度减少而增加是电极附近结区电场引起的。

The electric fields describing the property of the electrodes in n^+-i-n^+ devices have beenchosen as another set of boundary conditions for a system of differential equation of currentflow in a-Si:H devices. Using the Range-Kutta methods with Gill's modification, the differentialequations are solved by initial-value technique,and the J-V characteristics of the devices areobtained. The density of states for thin a-Si:H films are determinated using the SCLC technique,and it is concluded that the electric field at the junction region in n^+-i-n^+ devices resultsin the increase of the density of state at Fermi level as the thickness of the sample decreases.