Efficient silicon solar cells with highly conductive zirconium nitride electron-selective contacts

Abstract

Efficient carrier transport and suppressed interface recombination at back contact are essential for high-efficiency solar cells. Herein, we developed a zirconium nitride (ZrN) film with a low film resistivity of 1.6 × 10−4 Ω cm as an electron-selective contact for n-type silicon solar cells. Suitable band alignment of the n-Si/ZrN hetero-contact eliminates the interface barrier between Al and n-Si. Meanwhile, electrostatic potential induced by interfacial Si–O–Zr bonds assists electron extraction. The fill factor of devices has been significantly improved by incorporating a ZrN layer. After optimizing the thickness of ZrN and contact fraction, the champion ZrN-based device exhibited an efficiency of 19.7%, yielding a 23% enhancement compared with that without a ZrN interlayer.

ZrN films with low resistivity under different chamber pressures by MOCVD

“…With advancements in relevant theoretical investigation and material preparation technology, the application of ZrN in semiconductors and microelectronic devices has also shown enormous potential in recent years. It is extensively utilized in various kinds of microelectronic structures, such as a barrier layer in metallization schemes, 1 an electron selector in Si-based solar cells, 2 a plasmon material in magnetic recording and sensors, 3 and a low-resistance metal gate in MOS, 4 as well as superconducting devices. 5,6 Therefore, its related preparation technology and application development have gradually become one of the leading-edge hot spots.…”