Determination of deep-level defects in Cu2ZnSn(S,Se)4 thin-films using photocapacitance method

Islam, Muhammad Monirul; Halim, Mohammad A.; Sakurai, Takayasu; Sakai, Nobuo; Kato, Takuya; Sugimoto, H.; Tampo, Hitoshi; Shibata, Hajime; Niki, Shigeru; Akimoto, Katsuhiro

doi:10.1063/1.4922810

Cited by 23 publications

(27 citation statements)

References 27 publications

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“…Therefore, alternative but more demanding methods have been used so far, such as quantum effi ciency (QE) analysis, photoluminescence, or photocapacitance. [ 63,75 ] The red bars show the acceptor levels and the blue bars show the donor levels, with the initial and fi nal charge states labeled in parentheses. Reproduced with permission.…”

Section: Band Tailing and Its Potential Originmentioning

confidence: 99%

Is the Cu/Zn Disorder the Main Culprit for the Voltage Deficit in Kesterite Solar Cells?

Bourdais¹,

Choné²,

Delatouche³

et al. 2016

Advanced Energy Materials

302

239

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Section: Band Tailing and Its Potential Originmentioning

confidence: 99%

Is the Cu/Zn Disorder the Main Culprit for the Voltage Deficit in Kesterite Solar Cells?

Bourdais¹,

Choné²,

Delatouche³

et al. 2016

Advanced Energy Materials

302

239

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“…TPC [84] highest solar cell efficiencies have been achieved at low Cu and high Zn compositions which should decrease the formation of Cu Zn and promote the formation V Cu . The Zn-rich and Cu-poor compositions of CZTS and CZTSe should also help to avoid the formation of detrimental Sn-related deep defects such as Cu Sn , Sn Cu and Sn Zn and associated defect complexes.…”

Section: Intrinsic Defects In Kesteritesmentioning

confidence: 99%

The electrical and optical properties of kesterites

et al. 2019

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Kesterite Cu 2 ZnSn(S x Se 1-x ) 4 (CZTSSe) semiconductor materials have been extensively studied over the past decade, however despite significant efforts, the open circuit voltage remains below 60% of the theoretical maximum. Understanding the optical and electrical properties is critical to explaining and solving the voltage deficit. This review aims to summarize the present knowledge of optical and electrical properties of kesterites and specifically focuses on experimental data of intrinsic defects, charge carrier density and transport, and minority carrier lifetime and related rate-limiting recombination mechanisms. It concludes with suggestions for further investigation of the electrical and optical properties of kesterite materials. of the (001) cationic planes are randomly occupied by Cu and Zn atoms [6,7]. While theoretical calculations by Chen et al [8] find the lowest formation energy for the kesterite crystal structure, cation disorder is present in CZTSSe due to the low energy difference between the stannite-and kesterite-related structures. It has been suggested that the Cu-Zn disorder in Cu 2 ZnSnS 4 (CZTS) follows a second order phase transition with a critical temperature of ∼260°C for CZTS, which was first observed and introduced to describe the modifications in the Raman spectra of CZTS annealed at different temperatures [9]. A similar phenomenon has also been found in Cu 2 ZnSnSe 4 (CZTSe), with a critical temperature of 200°C [10], where the measured increase in band gap is explained by thermally induced ordering of Cu and Zn cations. While the remarkable effect of the orderdisorder transition on the band gap and vibrational spectra is explained by Vineyard's theory [11], the disorder parameter itself is not experimentally determined in the probed samples. A recent direct comparison between resonant x-ray diffraction and photoluminescence (PL) data in CZTSe has confirmed a relationship between the Cu-Zn disorder and the band gap modification [12]. A change in the order parameter from 0 to 0.7 leads to a OPEN ACCESS RECEIVED significant increase in the band gap on the order of ∼0.11 eV and ∼0.20 eV for CZTSe and CZTS, respectively [10,13].The absorption coefficient for CZTS and CZTSe is about ∼2-3 × 10 4 cm −1 at 1.6 eV and at 1.1 eV, respectively, as determined by the normal reflectance and transmittance [2, 13] spectroscopic ellipsometry (SE) [14-16] and external quantum efficiency [17] methods. In the recent review by Choi et al [18] the main theoretical and experimental results on the energy band structure and SE data were discussed and summarized. Recently, Zamulko et al [19] re-examined first principle theory at different levels in order to improve the description of the electronic structure and optical properties of CZTSSe. Nishiwaki et al [20] performed density functional calculation to study absorption band tail of the kesterites. In particular, a theoretical estimate for the tail energy of ∼30 meV for both CZTS and CZTSe was obtained. It was suggested that quite large Urbach energi...

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“…According to the reported information, such as the density and the carrier capture cross-section of the defects, measured by DLTS, here we can estimate the shortest carrier lifetime of CZTSSe by Equation (5). The calculated carrier lifetimes τ c are listed in Table 2 [89,90,101,[105][106][107][108][109][110][111][112]. Unexpectedly, the τ c values derived from the DLTS are in the order of microsecond or even millisecond, which is several orders of magnitude larger than the measured result (τ m ).…”

Section: Experimental Identification Of Defectsmentioning

confidence: 82%

“…Based on the above discussions, it can be found that the CZTSSe material indeed possesses more serious atomic disorder and band tail states compared with other semiconductors. A previous summary of the Urbach energy (E U ) of the CZTSSe and other materials clearly shows this fact [41,[88][89][90]. E U is also a featured parameter reflecting the band tail states.…”

Section: Cu/zn Disorder: Influencementioning

confidence: 88%

Underlying mechanism of the efficiency loss in CZTSSe solar cells: Disorder and deep defects

Duan

Shi

et al. 2020

Sci. China Mater.

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Although Cu 2 ZnSn(S x , Se 1−x) 4 (CZTSSe) is a promising candidate for thin-film photovoltaics, its cell performance is currently limited by the large voltage loss. Although a series of studies on the efficiency loss mechanism of CZTSSe solar cell have been carried out in the past few years, no convincing understanding has been obtained until now. In this review, the current findings regarding the underlying mechanism of the efficiency loss in CZTSSe solar cells are systematically summarized and analyzed. The properties of atomic disorder and deep defects in CZTSSe materials and their effects on device performance are discussed. The synergistic effect is proposed to help understand the defect-related charge loss in the absorber. Furthermore, the experimental methods of defect identification and defect control are presented, in an attempt to identify the killer defects that can be responsible for the ultra-short minority lifetime of CZTSSe material. By comprehensively and dialectically understanding these defect properties of the CZTSSe solar cell, we believe breakthrough in the cell efficiency will come soon with our concentrated effort.

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Determination of deep-level defects in Cu2ZnSn(S,Se)4 thin-films using photocapacitance method

Cited by 23 publications

References 27 publications

Is the Cu/Zn Disorder the Main Culprit for the Voltage Deficit in Kesterite Solar Cells?

Is the Cu/Zn Disorder the Main Culprit for the Voltage Deficit in Kesterite Solar Cells?

The electrical and optical properties of kesterites

Underlying mechanism of the efficiency loss in CZTSSe solar cells: Disorder and deep defects

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