发表机构
University of Virginia（弗吉尼亚大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
提出一种可迁移的全带蒙特卡洛框架，通过紧束缚能带计算和物理推导的合金无序散射模型，模拟复杂合金APD的雪崩增益与噪声，在Al0.7InAsSb器件上验证了实验数据。
AI 中文摘要
我们提出一个基于物理的多尺度全带蒙特卡洛框架，用于模拟复杂合金雪崩光电二极管（APD）中的雪崩倍增和过剩噪声，并以Al$_{0.7}$InAsSb作为代表性四元系进行演示。该框架将原子级材料结构连接到器件级雪崩统计：环境依赖的$sp^3d^5s^\ast$紧束缚计算解析了随机或数字合金构型的完整导带和价带结构——包括$\Gamma$、X和L谷排序、非抛物线型、各向异性以及自旋轨道诱导的价带分裂——并为随机高场输运提供能带结构输入。该框架的一个核心要素是对合金无序散射的物理推导处理，其中四元无序势由原子价差、共价半径和托马斯-费米屏蔽通过按组分加权的二元贡献分解构建，并辅以组分插值的极性光学、声学、谷间声子、杂质和碰撞电离模型。由于每个依赖材料的输入都由相同的明确定义程序从原子组成和构型生成，该框架无需结构修改即可迁移到任意闪锌矿三元和四元合金。应用于1微米Al$_{0.7}$InAsSb p-i-n APD时，该框架仅通过校准碰撞电离软化参数即可重现实测增益和过剩噪声特性。该方法为分析和设计能带结构、无序和散射物理共同决定增益和电离统计的复杂合金APD提供了一条有据可查、可复现的途径。
英文摘要
We present a physics-based multiscale full-band Monte Carlo framework for modeling avalanche multiplication and excess noise in complex alloy avalanche photodiodes (APDs), demonstrated on Al$_{0.7}$InAsSb as a representative quaternary system. The framework links atomistic material structure to device-level avalanche statistics: an environment-dependent $sp^3d^5s^\ast$ tight-binding calculation resolves the full conduction- and valence-band structure of the random- or digital-alloy configuration -- including $Γ$, X, and L valley ordering, non-parabolicity, anisotropy, and spin-orbit-induced valence-band splitting -- and supplies the band-structure inputs for stochastic high-field transport. A central element of the framework is a physics-derived treatment of alloy-disorder scattering, in which the quaternary disorder potential is constructed from atomic valence differences, covalent radii, and Thomas--Fermi screening through a composition-weighted decomposition into binary contributions, complemented by composition-interpolated polar-optical, acoustic, intervalley-phonon, impurity, and impact-ionization models. Because every material-dependent input is generated from the atomic composition and configuration by the same well-defined procedure, the framework transfers without structural modification to arbitrary zinc-blende ternary and quaternary alloys. Applied to a \SI{1}{\micro\meter} Al$_{0.7}$InAsSb p-i-n APD, the framework reproduces the measured gain and excess-noise characteristics with only the impact-ionization softness parameters calibrated. The approach provides a documented, reproducible route for analyzing and designing complex alloy APDs in which band structure, disorder, and scattering physics jointly determine gain and ionization statistics.
