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Title: High Carrier Lifetimes in Epitaxial Germanium-Tin/Al(In)As Heterostructures with Variable Tin Compositions

Abstract

Group IV-based germanium-tin (Ge1-ySny) compositional materials have recently shown great promise for infrared detection, light emission and ultra-low power transistors. High carrier lifetimes are desirable for enhancing the detection limit and efficiency of photodetectors, low threshold current density in lasers, and low tunneling barrier height by lowering defects and dislocations at the heterointerface of a source and a channel. Here, carrier lifetimes in epitaxial germanium (Ge) and variable tin (Sn) compositional Ge1-ySny materials were experimentally determined on GaAs substrates using the contactless microwave photoconductive decay (u-PCD) technique at an excitation wavelength of 1500 nm. Sharp (2 x 2) reflection high energy electron diffraction patterns and low surface roughness were observed from the surface of the Ge0.97Sn0.03 epilayer. X-ray rocking curves from Ge0.97Sn0.03 and Ge0.94Sn0.06 layers demonstrated the pseudomorphic and lattice-matched growth on AlAs and In0.12Al0.88As buffers, respectively, further substantiated by reciprocal space maps and abrupt heterointerfaces evident from the presence of Pendellosung oscillations. High effective carrier lifetimes of 150 ns to 450 ns were measured for Ge1-ySny epilayers as a function of Sn composition, surface roughness, growth temperature, and layer thickness. The observed increase in the carrier lifetime with an increasing Ge layer thickness and a reducing surface roughness, bymore » incorporating Sn, were explained. The enhancement of the carrier lifetime with an increasing Sn concentration was achieved by controlling the defects with lattice-matched Ge0.94Sn0.06/In0.12Al0.88As heterointerfaces or the pseudomorphic growth of Ge0.94Sn0.06 on GaAs. Therefore, our monolithic integration of variable Sn alloy compositional Ge1-ySny materials with high carrier lifetimes opens avenues to realize electronic and optoelectronic devices.« less

Authors:
; ORCiD logo; ; ; ;
Publication Date:
Research Org.:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org.:
USDOE National Renewable Energy Laboratory (NREL); National Science Foundation (NSF)
OSTI Identifier:
1880807
Report Number(s):
NREL/JA-5K00-81502
MainId:82275;UUID:f9b6ee5f-a033-45d0-9dcc-b2ac24b435ae;MainAdminID:65069
DOE Contract Number:  
AC36-08GO28308
Resource Type:
Journal Article
Journal Name:
Journal of Materials Chemistry C
Additional Journal Information:
Journal Volume: 10; Journal Issue: 29
Country of Publication:
United States
Language:
English
Subject:
INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY,MATERIALS SCIENCE; carrier lifetimes; contactless microwave photoconductive decay; epitaxial germanium; GeSn; variable tin

Citation Formats

Hudait, Mantu K., Johnston, Steven W., Clavel, Michael B., Bhattacharya, Shuvodip, Karthikeyan, Sengunthar, and Joshi, Rutwik. High Carrier Lifetimes in Epitaxial Germanium-Tin/Al(In)As Heterostructures with Variable Tin Compositions. United States: N. p., 2022. Web. doi:10.1039/D2TC00830K.
Hudait, Mantu K., Johnston, Steven W., Clavel, Michael B., Bhattacharya, Shuvodip, Karthikeyan, Sengunthar, & Joshi, Rutwik. High Carrier Lifetimes in Epitaxial Germanium-Tin/Al(In)As Heterostructures with Variable Tin Compositions. United States. https://doi.org/10.1039/D2TC00830K
Hudait, Mantu K., Johnston, Steven W., Clavel, Michael B., Bhattacharya, Shuvodip, Karthikeyan, Sengunthar, and Joshi, Rutwik. 2022. "High Carrier Lifetimes in Epitaxial Germanium-Tin/Al(In)As Heterostructures with Variable Tin Compositions". United States. https://doi.org/10.1039/D2TC00830K.
@article{osti_1880807,
title = {High Carrier Lifetimes in Epitaxial Germanium-Tin/Al(In)As Heterostructures with Variable Tin Compositions},
author = {Hudait, Mantu K. and Johnston, Steven W. and Clavel, Michael B. and Bhattacharya, Shuvodip and Karthikeyan, Sengunthar and Joshi, Rutwik},
abstractNote = {Group IV-based germanium-tin (Ge1-ySny) compositional materials have recently shown great promise for infrared detection, light emission and ultra-low power transistors. High carrier lifetimes are desirable for enhancing the detection limit and efficiency of photodetectors, low threshold current density in lasers, and low tunneling barrier height by lowering defects and dislocations at the heterointerface of a source and a channel. Here, carrier lifetimes in epitaxial germanium (Ge) and variable tin (Sn) compositional Ge1-ySny materials were experimentally determined on GaAs substrates using the contactless microwave photoconductive decay (u-PCD) technique at an excitation wavelength of 1500 nm. Sharp (2 x 2) reflection high energy electron diffraction patterns and low surface roughness were observed from the surface of the Ge0.97Sn0.03 epilayer. X-ray rocking curves from Ge0.97Sn0.03 and Ge0.94Sn0.06 layers demonstrated the pseudomorphic and lattice-matched growth on AlAs and In0.12Al0.88As buffers, respectively, further substantiated by reciprocal space maps and abrupt heterointerfaces evident from the presence of Pendellosung oscillations. High effective carrier lifetimes of 150 ns to 450 ns were measured for Ge1-ySny epilayers as a function of Sn composition, surface roughness, growth temperature, and layer thickness. The observed increase in the carrier lifetime with an increasing Ge layer thickness and a reducing surface roughness, by incorporating Sn, were explained. The enhancement of the carrier lifetime with an increasing Sn concentration was achieved by controlling the defects with lattice-matched Ge0.94Sn0.06/In0.12Al0.88As heterointerfaces or the pseudomorphic growth of Ge0.94Sn0.06 on GaAs. Therefore, our monolithic integration of variable Sn alloy compositional Ge1-ySny materials with high carrier lifetimes opens avenues to realize electronic and optoelectronic devices.},
doi = {10.1039/D2TC00830K},
url = {https://www.osti.gov/biblio/1880807}, journal = {Journal of Materials Chemistry C},
number = 29,
volume = 10,
place = {United States},
year = {2022},
month = {6}
}

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