Improved electrical properties of silicon quantum dot layers for photovoltaic applications

Hong, Sunwook; Baek, In Bok; Kwak, Gyea Young; Lee, Seong Hyun; Jang, Jong Shik; Kim, Kyung Joong; Kim, Ansoon

doi:10.1016/j.solmat.2016.01.034

Cited by 10 publications

(2 citation statements)

References 22 publications

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“…The electroluminescence efficiency in SiGe based on alloys is only about 0.1% at room temperature . The confinement of electrons in Si and Ge , quantum dots (QDs), or in more complex defect engineered QDs in Ge, was studied as a solution to improve their photonic properties. The quantum confinement results in local increase of the optical transition probability but also in lower absorption in the assemble of QDs as well as blue-shift of the optical bandgap. − …”

Section: Introductionmentioning

confidence: 99%

GeSn Nanocrystals in GeSnSiO₂ by Magnetron Sputtering for Short-Wave Infrared Detection

Slav

Palade

Logofatu

et al. 2019

ACS Appl. Nano Mater.

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Detection in short-wave infrared (SWIR) has become a very stringent technology requirement for developing fields like hyperspectral imaging or climate changes. In a market dominated by III–V materials, GeSn, a Si compatible semiconductor, has the advantage of cost efficiency and inerrability by using the mature Si technology. Despite the recent progress in material growth, the easy fabrication of crystalline GeSn still remains a major challenge, and different methods are under investigation. We present the formation of GeSn nanocrystals (NCs) embedded in oxide matrix and their SWIR characterization. The simple and cost-effective fabrication method is based on thermal treatment of amorphous (Ge1–x Sn x ) y (SiO2)1–y layers deposited by magnetron sputtering. The nanocrystallization for Ge1–x Sn x with 9–22 at. % Sn composition in SiO2 matrix with 9% to 15% mole percent was studied under low thermal budget annealing in the 350–450 °C temperature range. While the Sn at.% content is the main parameter influencing the band-structure of the NCs, the SWIR sensitivity can be optimized by SiO2 content and H2 gas component in the deposition atmosphere. Their role is not only changing the crystallization parameters but also to reduce the carrier recombination by passivation of NCs defects. The experiments indicate a limited composition dependent temperature range for GeSn NCs formation before β-Sn phase segregation occurs. NCs with an average size of 6 nm are uniformly distributed in the film, except the surface region where larger GeSn NCs are formed. Spectral photovoltaic current measured on SiO2 embedded GeSn NCs deposited on p-Si substrate shows extended SWIR sensitivity up to 2.4 μm for 15 at. % Sn in GeSn NCs. The large extension of the SWIR detection is a result of many factors related to the growth parameters and also to the in situ or ex situ annealing procedures that influence the uniformity and size distribution of NCs.

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Section: Introductionmentioning

confidence: 99%

GeSn Nanocrystals in GeSnSiO₂ by Magnetron Sputtering for Short-Wave Infrared Detection

Slav

Palade

Logofatu

et al. 2019

ACS Appl. Nano Mater.

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“…First, the doping concentration of B was optimized. The B-doped Si-QD active layer was formed and activated by annealing the SiO x :B layer at 1100 °C for 60 min [28,29]. A high concentration of B atoms is required for the activation of B atoms in the Si-QD layer.…”

Section: Resultsmentioning

confidence: 99%

Improvement of power conversion efficiency by a stepwise band-gap structure for silicon quantum dot solar cells

Kwak¹,

Kim²,

Kim³

et al. 2020

Nanotechnology

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As a promising next-generation solar cell, the power conversion efficiency of a silicon quantum dot (Si-QD) solar cell is still low. In this work, the band-gap structure of a Si-QD layer was modified to improve the power conversion efficiency of a Si-QD solar cell. A stepwise band-gap Si-QD (SB Si-QD) layer with a high bandgap top layer (about 2.22 eV) and a low band-gap bottom layer (about 1.98 eV) was grown on a Si (100) substrate. The open circuit voltage and short circuit current were improved by band-gap engineering of the Si-QD absorption layer. As a result, the power conversion efficiency of the SB Si-QD solar cell increased from 16.50% to 17.50%, compared to that of a Si-QD solar cell with a uniform band gap. This results will provide a guide to design advanced Si-QD solar cells by considering the band-gap structure in the Si-QD absorption layer.

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Opto-structural properties of Si-rich SiNx with different stoichiometry

Tiour

Benyahia²,

Brihi

et al. 2020

Appl. Phys. A

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Improved electrical properties of silicon quantum dot layers for photovoltaic applications

Cited by 10 publications

References 22 publications

GeSn Nanocrystals in GeSnSiO₂ by Magnetron Sputtering for Short-Wave Infrared Detection

GeSn Nanocrystals in GeSnSiO₂ by Magnetron Sputtering for Short-Wave Infrared Detection

Improvement of power conversion efficiency by a stepwise band-gap structure for silicon quantum dot solar cells

Opto-structural properties of Si-rich SiNx with different stoichiometry

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Improved electrical properties of silicon quantum dot layers for photovoltaic applications

Cited by 10 publications

References 22 publications

GeSn Nanocrystals in GeSnSiO2 by Magnetron Sputtering for Short-Wave Infrared Detection

GeSn Nanocrystals in GeSnSiO2 by Magnetron Sputtering for Short-Wave Infrared Detection

Improvement of power conversion efficiency by a stepwise band-gap structure for silicon quantum dot solar cells

Opto-structural properties of Si-rich SiNx with different stoichiometry

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Product

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GeSn Nanocrystals in GeSnSiO₂ by Magnetron Sputtering for Short-Wave Infrared Detection

GeSn Nanocrystals in GeSnSiO₂ by Magnetron Sputtering for Short-Wave Infrared Detection