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Main Authors: Magginetti, David, Jeon, Seokmin, Yoon, Yohan, Choudhury, Ashif, Mamun, Ashraful, Qian, Yang, Gerton, Jordan, Yoon, Heayoung
Format: Preprint
Published: 2023
Subjects:
Online Access:https://arxiv.org/abs/2302.00613
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author Magginetti, David
Jeon, Seokmin
Yoon, Yohan
Choudhury, Ashif
Mamun, Ashraful
Qian, Yang
Gerton, Jordan
Yoon, Heayoung
author_facet Magginetti, David
Jeon, Seokmin
Yoon, Yohan
Choudhury, Ashif
Mamun, Ashraful
Qian, Yang
Gerton, Jordan
Yoon, Heayoung
contents Microstructural properties of thin-film absorber layers play a vital role in developing high-performance solar cells. Scanning probe microscopy is frequently used for measuring spatially inhomogeneous properties of thin-film solar cells. While powerful, the nanoscale probe can be sensitive to the roughness of samples, introducing convoluted signals and unintended artifacts into the measurement. Here, we apply a glancing-angle focused ion beam (FIB) technique to reduce the surface roughness of CdTe while preserving the subsurface optoelectronic properties of the solar cells. We compare the nanoscale optoelectronic properties before and after the FIB polishing. Simultaneously collected Kelvin-probe force microscopy (KPFM) and atomic force microscopy (AFM) images show that the contact potential difference (CPD) of CdTe pristine (peak-to-valley roughness of approximately 600 nm) follows the topography. In contrast, the CPD map of polished CdTe (roughness of approximately 20 nm) is independent of the surface roughness. We demonstrate the smooth CdTe surface also enables high-resolution photoluminescence (PL) imaging at a resolution much smaller than individual grains (< 1 micrometer). Our finite-difference time-domain (FDTD) simulations illustrate how the local light excitation interacts with CdTe surfaces. Our work supports low-angle FIB polishing can be beneficial in studying buried sub-microstructural properties of thin-film solar cells with care for possible ion-beam damage near the surface.
format Preprint
id arxiv_https___arxiv_org_abs_2302_00613
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Impact of Surface Roughness in Measuring Optoelectronic Characteristics of Thin-Film Solar Cells
Magginetti, David
Jeon, Seokmin
Yoon, Yohan
Choudhury, Ashif
Mamun, Ashraful
Qian, Yang
Gerton, Jordan
Yoon, Heayoung
Applied Physics
Optics
Microstructural properties of thin-film absorber layers play a vital role in developing high-performance solar cells. Scanning probe microscopy is frequently used for measuring spatially inhomogeneous properties of thin-film solar cells. While powerful, the nanoscale probe can be sensitive to the roughness of samples, introducing convoluted signals and unintended artifacts into the measurement. Here, we apply a glancing-angle focused ion beam (FIB) technique to reduce the surface roughness of CdTe while preserving the subsurface optoelectronic properties of the solar cells. We compare the nanoscale optoelectronic properties before and after the FIB polishing. Simultaneously collected Kelvin-probe force microscopy (KPFM) and atomic force microscopy (AFM) images show that the contact potential difference (CPD) of CdTe pristine (peak-to-valley roughness of approximately 600 nm) follows the topography. In contrast, the CPD map of polished CdTe (roughness of approximately 20 nm) is independent of the surface roughness. We demonstrate the smooth CdTe surface also enables high-resolution photoluminescence (PL) imaging at a resolution much smaller than individual grains (< 1 micrometer). Our finite-difference time-domain (FDTD) simulations illustrate how the local light excitation interacts with CdTe surfaces. Our work supports low-angle FIB polishing can be beneficial in studying buried sub-microstructural properties of thin-film solar cells with care for possible ion-beam damage near the surface.
title Impact of Surface Roughness in Measuring Optoelectronic Characteristics of Thin-Film Solar Cells
topic Applied Physics
Optics
url https://arxiv.org/abs/2302.00613