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QuantumATK => General Questions and Answers => Topic started by: wot19920302 on April 20, 2019, 05:19

Title: Must electron-phonon coupling (EPC) be used for photocurrent for indirect band?
Post by: wot19920302 on April 20, 2019, 05:19

Dear Quantumwise staffs,
           Recently I have read the paper Efficient First-Principles Calculation of Phonon-Assisted Photocurrent in Large-Scale Solar-Cell Devices
. It can be seen phonon plays an important role in calculating photocurrent for inderect energy gap materials. However, phonon calculation using DFT is pretty expensive and time-consuming. So I want to know if there is one material with small difference between direct gap and indirect gap (e.g. direct gap :0.42 eV, indirect gap: 0.38 eV), under low temperature condition (i.e. phonon effect is suppressed), is it reasonable to calculate photocurrent  not considering EPC? Does  the calculated photocurrent  mainly come from transition of electrons through direct gap?
          Best wishes

Title: Re: Must electron-phonon coupling (EPC) be used for photocurrent for indirect band?
Post by: Petr Khomyakov on April 24, 2019, 10:47

Quote from: wot19920302 on April 20, 2019, 05:19

is it reasonable to calculate photocurrent  not considering EPC? Does  the calculated photocurrent  mainly come from transition of electrons through direct gap?

I think the answers to your questions are already in the paper you have mentioned, e.g., see Fig. 2.