A semi-Lagrangian-type advection scheme, the constrained profile interpolation (CIP) method, is adopted to obtain a numerical solution of a drift–diffusion equation of photo-generated charge carriers in negatively biased, high-resistivity semiconductor detector materials. Transient current waveforms of high-resistivity CdZnTe measured by a time-of-flight (TOF) technique under different bias voltages and various laser excitation intensities, are theoretically reproduced from the temporal evolution of the charge distribution and corresponding internal electric-field evolution, which are derived from the solution of the drift–diffusion equation, in combination with Poisson’s equation. The temporal evolution of the charge distribution and internal electric-field distribution obtained by the present theoretical technique agree very well with those obtained by a Monte Carlo (MC) simulation, an independent numerical technique. We demonstrate the validity of the present numerical technique by reproducing the excitation-intensity dependence of experimental TOF current waveforms measured in a CdZnTe crystal.

采用半拉格朗日平流方案，即约束轮廓插值（CIP）方法，来获得负偏压，高电阻率半导体检测器材料中光生电荷载流子的漂移扩散方程的数值解。从飞行时间（TOF）技术在不同的偏置电压和不同的激光激发强度下测量的高电阻率CdZnTe瞬态电流波形在理论上是根据电荷分布的时间演化和相应的内部电场演化而重现的。由泊松方程与漂移扩散方程的解得出。通过本理论技术获得的电荷分布和内部电场分布的时间演化与通过独立数值技术的蒙特卡洛（MC）模拟获得的电荷演化和内部电场分布的时间演化非常吻合。我们通过再现在CdZnTe晶体中测量的实验TOF电流波形的激发强度依赖性来证明本数值技术的有效性。