Effects of Impact Ionization on the Photo-response of a small and Direct Band-gap Bulk Semiconductor

Abstract

In This Study, The Effects Of Impact Ionization And Optical Generation Of Carriers On The Photo Response Of Gallium Antimonide (Gasb) Is Described Through The Simulation Of Excess Carrier Lifetimes Corresponding To The Auger And Radiative Recombination Mechanisms Using The Relations Describing The Lifetimes Of The Excess Minority Carriers In The Bulk Of Direct Band Gap Semiconductor. First, The Room Temperature Doping Level Dependence Of Excess Carrier Lifetimes Related To The Radiative And Auger Recombination Mechanisms And The Combined Effect Of The Two Recombination Mechanisms Were Described. Then, The Temperature Dependence Of The Excess Carrier Lifetimes Was Described Using The Simulation Of The Temperature Dependence Of The Thermal Equilibrium Carrier Concentration Obtained Using The Hall Effect Measurements For The Samples With Different Doping Levels Along With The Relations Describing The Lifetimes Of The Excess Minority Carriers In The Bulk Of Direct Band Gap Semiconductor. Finally, The Room Temperature Injection Level Dependence Of The Steady State Excess Carrier Lifetimes Was Described In Samples With Different Doping Levels By Varying Excess Carrier?�?S Concentration From Very Low Injection Level To Very High Injection Level. Since Gasb Is A Small And Direct Band Gap Semiconductor, All The Intra-Band Transitions Were Neglected And Only Inter-Band Generation-Recombination Of Free Carriers Was Considered. The Effective Excess Carrier Lifetime For Free Carriers Is In General Found To Be Decreasing With Increasing The Doping Level And The Injection Level Of Excess Carriers. The Radiative Effect Is Found To Be Influential In The Lower Doping Level Regime And Lower Injection Ranges Of Injection Levels, While The Impact Ionization Totally Dominates The Higher Doping Regime And Higher Injection Level. Even Though The Impact Ionization Highly Dominates The Higher Temperature Region Of The Entire Excess Carrier Lifetime, The Variation In Both The Radiative And The Auger Effect Have No Significant Difference In The Complete Ionization Region Temperature Region. The Variation Of The Excess Carrier Lifetimes Was Intensified In The Low Temperature Region Due To Freeze-Out Of Charge Carriers And At High Temperature Due To Intrinsic Effect. As The Temperature Increases, The Excess Carrier Lifetime Decreases, And The Impact Ionization Totally Dominates In The Higher Temperature Regime. Because Of The Auger And Radiative Recombination Mechanisms Are The Reverse Processes Of The Impact Ionization And Optical Generation, Respectively, The Two Reverse Process Are Equal By The Principle Of The Detailed Balance.