Monte Carlo Modeling of Electron Transport and Capture Processes in AlGaAs/GaAs Multiple Quantum Well Infrared Photodetectors

Abstract

The results of an ensemble Monte Carlo (MC) particle modeling of vertical electron transport and capture processes in AlGaAs/GaAs multiple quantum well infrared photodetectors (QWIPs) are presented. The MC model employed takes into account features of the conduction band structure, the electron scattering parameters, and the interaction (reflection, transmission and capture) of free electrons with the QWs. It is shown that the heating of free electrons and their redistribution over the conduction band valleys under the influence of electric field play an essential role in both the transport processes and the capture into bound states in the QWs. The electron drift velocity and macroscopic capture parameter are calculated as functions of the structural parameters and applied electric field. The capture parameter exhibits a pronounced drop with increasing electric field due to a significant decrease of the fraction of electrons with energies less than the optical phonon energy.

Nonlocal Hot-Electron Transport and Capture Model for Multiple Quantum Well Structures Excited by Infrared Radiation

“…As can be seen from eqs. (16) and (18), the amplitude of the periodic electric-field structure increases with receding from the threshold. Equations (18) and (20) show that the formation of periodic electric-field domains and the increase in their amplitude with increasing donor concentration lead to a sublinear dependence of the photocurrent on this concentration.…”

“…24 and references therein) and in MC simulations. 16,17) However, the electric-field dependence of the capture rate and, consequently, the capture parameter become complex when the electric field is not uniform. It was assumed in phenomenological models of the electron transport in multiple QW structures 9,11,14,15) that the capture rate into a QW is determined by an active field which, in turn, is determined by the electric fields at both sides of this QW.…”

“…The electron system in multiple QW structures excited by infrared radiation at relatively high bias voltages standard for QW infrared photodetector operation conditions is far from equilibrium. 16,17) In particular, the mobile electrons heated by the electric field can be well spread over the continuum states (in different valleys of the conduction band) above the barriers. The nonlocal nature of the relationship between the spatial distributions of the electric field and the average energy of mobile electrons can essentially manifest itself in transport phenomena under such conditions.…”

Monte-Carlo simulation for QDIP device design

“…Monte-Carlo simulation method has been widely used to calculate the electron transport in semiconductor devices [11][12][13][14][15]. In this method, sets of random numbers are used to execute the simulation in order to determine the type of the scattering phenomena that can be expected in semiconductor materials etc.…”

Nonlinear dynamics of recharging processes in multiple quantum well structures excited by infrared radiation

“…1 Several physical models using both analytical and numerical simulation approaches have been proposed for steady-state and transient operation of QWIP's. [12][13][14][15][16][17][18][19][20][21][22][23][24][25] Early models of QWIP's with multiple QW's assumed that the electric-field distribution in the active region is uniform. 12,13 Later, it has been shown that the space charge gives rise to the nonuniformity of the electric field either near the emitter contact 15,17,[19][20][21] or spread across the whole structure.…”