Electrical and optical characterization of CdTe solar cells with CdS and CdSe buffers—A comparative study

Journal Article · Wed Sep 05 00:00:00 EDT 2018 · Journal of Vacuum Science and Technology B

DOI:https://doi.org/10.1116/1.5044219· OSTI ID:1579313

Mia, Md Dalim ^[1]; Swartz, Craig H. ^[1]; Paul, Sanjoy ^[1]; Sohal, Sandeep ^[1]; Grice, Corey R. ^[2]; Yan, Yanfa ^[2]; Holtz, Mark ^[1]; Li, Jian V. ^[3]

---

1. Texas State Univ., San Marcos, TX (United States)
2. The Univ. of Toledo, Toledo, OH (United States)
3. National Cheng Kung Univ., Tainan Taiwan

A study is reported comparing the electrical and optical properties of CdTe solar cells, prepared using CdS and CdSe buffer layers, to investigate defects in the bulk and interface, carrier transport, and recombination. Temperature dependent capacitance-voltage measurement and admittance spectroscopy were used to extract carrier concentration, resistivity, charge carrier mobility, and their temperature dependence. We identify the presence of two defect signatures corresponding to carrier freeze-out and the formation of a Schottky back-contact barrier. The back-contact barrier height (≈ 300 meV) extracted from the temperature dependent current density-voltage (JVT) experiment was confirmed by conventional admittance spectroscopy. The activation energies of mobility (resistivity) are 101.2 ± 2.5 meV (92.6 ± 2.3 meV) and 84.7 ± 2.7 meV (77.6 ± 4.5 meV) for CdS and CdSe buffer layers, respectively. Intensity dependent photoluminescence analysis demonstrates that the CdSe/CdTe device exhibits lower radiative efficiency than the CdS/CdTe device. This confirms the presence of higher defects in CdSe/CdTe device corroborated by temperature-dependent V_OC analysis. Here, the comparative electrical and optical analysis provides insight to improving the performance of CdTe solar cell device by selenization.

• Research Organization: Texas State Univ., San Marcos, TX (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE), Renewable Power Office. Solar Energy Technologies Office
• Grant/Contract Number: EE0007541
• OSTI ID: 1579313
• Alternate ID(s): OSTI ID: 1468674
• Journal Information: Journal of Vacuum Science and Technology B, Vol. 36, Issue 5; ISSN 2166-2746
• Publisher: American Vacuum Society/AIP
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY