Electrical properties of CdS/Cu(In,Ga)Se₂ interface

Journal Article · 27 June 2018 · Japanese Journal of Applied Physics

DOI: https://doi.org/10.7567/JJAP.57.085701 · OSTI ID:1462332

Li, Jian V. ^[1]; Mansfield, Lorelle M. ^[2]; Egaas, Brian ^[2]; Ramanathan, Kannan ^[2]

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1. National Cheng Kung Univ., Tainan City (Taiwan)
2. National Renewable Energy Lab. (NREL), Golden, CO (United States)

We present an experimental method to measure and extract the interface density of states and fixed charge at the CdS/Cu(In,Ga)Se₂ (CIGS) interface using the capacitance-voltage technique applied to a metal-insulator-semiconductor structure. The density of interface states is on the order of 10¹⁰ to 10¹³ cm^-2 eV^-1. The effective fixed charge at the interface is (7.8 +/- 0.3) x 10¹¹ cm^-2 and due to positive charges. These electrical properties make the CdS/CIGS interface well passivated and to some extent resemble the SiN _x /p-Si interface. We also measure the inversion strength (i.e., Fermi level at the interface) and capture cross-section of interface states from admittance spectroscopy. Inputting the above extracted parameters into the extended Shockley-Read-Hall recombination formulation by Eades and Swanson [J. Appl. Phys. 58, 4267 (1985)], we calculate the surface recombination velocity of mid-to-high 10³ cm•s^–1, which agrees reasonably with temperature-intensity dependent recombination analysis.

• Research Organization: National Renewable Energy Lab. (NREL), Golden, CO (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE), Solar Energy Technologies Office (EE-4S)
• Grant/Contract Number: AC36-08GO28308
• OSTI ID: 1462332
• Report Number(s): NREL/JA--5K00-72040
• Journal Information: Japanese Journal of Applied Physics, Journal Name: Japanese Journal of Applied Physics Journal Issue: 8 Vol. 57; ISSN 0021-4922
• Publisher: Japan Society of Applied PhysicsCopyright Statement
• Country of Publication: United States
• Language: English