Formation and Evaluation of Silicon Substrate with Highly-Doped Porous Si Layers Formed by Metal-Assisted Chemical Etching

Porous silicon (Si) is a low thermal conductivity material, which has high potential for thermoelectric devices. However, low output performance of porous Si hinders the development of thermoelectric performance due to low electrical conductivity. The large contact resistance from nonlinear contact...

Full description

Saved in:

Bibliographic Details
Published in:	Nanoscale research letters Vol. 16; no. 1; p. 64
Main Authors:	Li, Yijie, Van Toan, Nguyen, Wang, Zhuqing, Samat, Khairul Fadzli Bin, Ono, Takahito
Format:	Journal Article
Language:	English
Published:	New York Springer US 20-04-2021 Springer Nature B.V SpringerOpen
Subjects:	Carrier density Chemical etching Chemistry and Materials Science Contact resistance Electric contacts Electrical conductivity Electrical resistivity Etching Materials Science Metal-assisted chemical etching Molecular Medicine Nano Express Nanochemistry Nanoscale Science and Technology Nanotechnology Nanotechnology and Microengineering Performance evaluation Porous Si Porous silicon Power factor Seebeck effect Silicon Silicon substrates Spin on dopant Substrates Thermal conductivity Thermoelectric Thermoelectric materials Thermoelectricity Spin on dopant Thermoelectric Power factor Metal-assisted chemical etching Porous Si
Online Access:	Get full text
Tags:	Add Tag No Tags, Be the first to tag this record!

Description
Summary:	Porous silicon (Si) is a low thermal conductivity material, which has high potential for thermoelectric devices. However, low output performance of porous Si hinders the development of thermoelectric performance due to low electrical conductivity. The large contact resistance from nonlinear contact between porous Si and metal is one reason for the reduction of electrical conductivity. In this paper, p - and n -type porous Si were formed on Si substrate by metal-assisted chemical etching. To decrease contact resistance, p - and n -type spin on dopants are employed to dope an impurity element into p - and n -type porous Si surface, respectively. Compared to the Si substrate with undoped porous samples, ohmic contact can be obtained, and the electrical conductivity of doped p - and n -type porous Si can be improved to 1160 and 1390 S/m, respectively. Compared with the Si substrate, the special contact resistances for the doped p - and n -type porous Si layer decreases to 1.35 and 1.16 mΩ/cm 2 , respectively, by increasing the carrier concentration. However, the increase of the carrier concentration induces the decline of the Seebeck coefficient for p - and n -type Si substrates with doped porous Si samples to 491 and 480 μV/K, respectively. Power factor is related to the Seebeck coefficient and electrical conductivity of thermoelectric material, which is one vital factor that evaluates its output performance. Therefore, even though the Seebeck coefficient values of Si substrates with doped porous Si samples decrease, the doped porous Si layer can improve the power factor compared to undoped samples due to the enhancement of electrical conductivity, which facilitates its development for thermoelectric application.
Bibliography:	ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23
ISSN:	1931-7573 1556-276X 1556-276X
DOI:	10.1186/s11671-021-03524-z