Advanced passivation techniques for Si solar cells with high-κ dielectric materials

Abstract

Electronic recombination losses at the wafer surface significantly reduce the efficiency of Si solar cells. Surface passivation using a suitable thin dielectric layer can minimize the recombination losses. Herein, advanced passivation using simple materials (Al2O3, HfO2) and their compounds H(Hf)A(Al)O deposited by atomic layer deposition (ALD) was investigated. The chemical composition of Hf and Al oxide films were determined by X-ray photoelectron spectroscopy (XPS). The XPS depth profiles exhibit continuous uniform dense layers. The ALD-Al2O3 film has been found to provide negative fixed charge (−6.4 × 1011 cm−2), whereas HfO2 film provides positive fixed charge (3.2 × 1012 cm−2). The effective lifetimes can be improved after oxygen gas annealing for 1 min. I-V characteristics of Si solar cells with high-κ dielectric materials as passivation layers indicate that the performance is significantly improved, and ALD-HfO2 film would provide better passivation properties than that of the ALD-Al2O3 film in this research work.

Low-Temperature One-Step Growth of AlON Thin Films with Homogenous Nitrogen-Doping Profile by Plasma-Enhanced Atomic Layer Deposition

“…Moreover, the existence of the N–Al–O bond confirms the formation of ternary compound of AlO x N y in the AlON sample. , It reveals that the prepared AlON sample is not a “mixture” of AlN and Al 2 O 3 . Normally, the ALD growth of ternary compound is realized by alternately growing two kinds of binary compounds. − In addition, there is no obvious subpeak shown in >400 eV range, which is commonly observed by the AlON films grown with high-temperature method . The absence of the N–O bond in the AlON film is probably due to the relatively low growth temperature and plasma power.…”

Interfacial and electrical properties of nanolaminated HfO2/Al2O3 dielectrics on GaN with an AlN interlayer

“…Figure 6 shows the Hf 4f core level spectra obtained at different etch depths (here, ed means etch depth). At HfO 2 surface, both samples revealed the peak energies of the Hf 4f 7/2 and Hf 4f 5/2 doublets at ∼16.2 and ∼17.8 eV, respectively, associated with HfO 2 [28]. With increasing the etch depth, these values shifted to higher binding energies such as ∼18.1 and ∼20.1 eV for the Hf 4f 7/2 and Hf 4f 5/2 peaks, respectively.…”

Structure, chemistry and luminescence properties of dielectric La Hf1-O films

“…Their unusual electrical, magnetic, dielectric, optical, and catalytic properties make them attractive materials for the production of solid oxide fuel cells, oxygen sensors, thermistors, resistors, and switches [1]. Thin films based on these compounds are of great interest as high-k materials used in the technology of solar cells [2]. As known, hafnium oxide has three polymorphs.…”