Theoretical analysis of non-radiative multiphonon recombination activity of intrinsic defects in CdTe
Theoretical analysis of non-radiative multiphonon recombination activity of intrinsic defects in CdTe
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DOI：
10.1063/1.4942529
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发表时间：
2016-02-28
影响因子：
3.2
通讯作者：
Sommerer, T. J.
中科院分区：
文献类型：
--
作者：
Krasikov, D. N.;Scherbinin, A. V.;Sommerer, T. J.
基于多声子单模载流子俘获模型，利用混合密度泛函理论计算了CdTe中本征缺陷（V-Cd，Te-Cd，V-Te和Te-i）的复合活性.这种分析使我们能够确定对电子、空穴或两者具有高捕获率的缺陷和相应的电子过程。后者，是潜在的最活跃的复合中心，减少了在CdTe太阳能电池的吸收层中的载流子寿命。考虑到Te-Cd反位缺陷的计算俘获截面相对较高，（在室温下，对于Te-Cd（+2）缺陷上的电子捕获，σ = 8.7 × 10（-15）cm（2），对于Te-Cd（+1）缺陷上的空穴捕获，σ = 6.8 × 10（-14）cm（2））和其深捕获水平（+2/+1能级为0.41 eV），表明该缺陷是p型CdTe中本征缺陷中最活跃的复合中心。其他不会导致有效重组的过程是：（i）Te-i（+1）缺陷上的快速空穴捕获（σ = 1.1 × 10（-13）cm（-2）），（ii）Te-Cd（+1）缺陷上的电子捕获（σ = 2.9 × 10（-15）cm（-2）），（iii）Te-Cd（0）缺陷上的空穴捕获稍慢（σ = 9.4 × 10（-20）cm（-2）），（iv）V-Cd（-1）缺陷上的空穴捕获（σ = 7 × 10（-19）cm（-2）），和（v）Te-1（+1）缺陷上的电子捕获（σ = 4.4 × 10（-19）cm（-2））。其余的捕获过程的横截面被发现是微不足道的小。VC 2016 AIP Publishing LLC.
We present an analysis of recombination activity of intrinsic defects (V-Cd, Te-Cd, V-Te, and Te-i) in CdTe based on the multiphonon single-mode carrier-capture model, with vibronic parameters obtained using hybrid density functional theory. This analysis allows us to determine the defects and the corresponding electronic processes that have high trapping rates for electrons, for holes, or for both. The latter, being potentially the most active recombination centers, decreases the carrier lifetime in the absorber layer of a CdTe solar cell. Taking into account the relatively high calculated capture cross-sections of the Te-Cd antisite defect (sigma = 8.7 x 10(-15) cm(2) for electron capture on Te-Cd(+2) defect, sigma = 6.8 x 10(-14) cm(2) for hole capture on Te-Cd(+1) defect at room temperature) and its deep trapping level (0.41 eV for +2/+1 level), we conclude that this defect is the most active recombination center among the intrinsic defects in p-type CdTe. Other processes that do not lead to effective recombination are: (i) fast hole capture on Te-i(+1) defect (sigma = 1.1 x 10(-13) cm(-2)), (ii) electron capture on Te-Cd(+1) defect (sigma = 2.9 x 10(-15) cm(-2)), (iii) somewhat slower hole capture on Te-Cd(0) defect (sigma = 9.4 x 10(-20) cm(-2)), (iv) hole capture on V-Cd(-1) defect (sigma = 7 x 10(-19) cm(2)), and (v) electron capture on Te-i(+1) defect (sigma = 4.4 x 10(-19) cm(-2)). The cross-sections are found to be negligibly small for the remaining capture processes. VC 2016 AIP Publishing LLC.