RT Journal Article
T1 Gold-hyperdoped Germanium with Room-Temperature Sub-bandgap Optoelectronic Response
T2 Gold-hyperdoped Germanium with Room-Temperature Sub-bandgap Optoelectronic Response
A1 Gandhi, Hemi H.
A1 Tran, Tuan T.
A1 Kalchmair, S.
A1 Pastor Pastor, David
A1 Smilie, L. A.
A1 Mailoa, Jonathan P.
A1 Milazzo, Ruggero
A1 Napolitani, Enrico
A1 Loncar, Marco
A1 Williams, James S.
A1 Aziz, Michael J.
A1 Mazur, Eric
AB Hyperdoping germanium with gold is a potential method to produce room-temperature short-wavelength-infrared radiation (SWIR; 1.4–3.0μm) photodetection. We investigate the charge carrier dynamics, light absorption, and structural properties of gold-hyperdoped germanium (Ge:Au) fabricated with varying ion implantation and nanosecond pulsed laser melting conditions. Time-resolved terahertz spectroscopy (TRTS) measurements show that Ge:Au carrier lifetime is significantly higher than that in previously studied hyperdoped silicon systems. Furthermore, we find that lattice composition, sub-band-gap optical absorption, and carrier dynamics depend greatly on hyperdoping conditions. We use density functional theory (DFT) to model dopant distribution, electronic band structure, and optical absorption. These simulations help explain experimentally observed differences in optical and optoelectronic behavior across different samples. DFT modeling reveals that substitutional dopant incorporation has the lowest formation energy and leads to deep energy levels. In contrast, interstitial or dopant-vacancy complex incorporation yields shallower energy levels that do not contribute to sub-band-gap light absorption and have a small effect on charge carrier lifetimes. These results suggest that it is promising to tailor dopant incorporation sites of Ge:Au for SWIR photodetection applications.
AB Hyperdoping germanium with gold is a potential method to produce room-temperature short-wavelength-infrared radiation (SWIR; 1.4–3.0μm) photodetection. We investigate the charge carrier dynamics, light absorption, and structural properties of gold-hyperdoped germanium (Ge:Au) fabricated with varying ion implantation and nanosecond pulsed laser melting conditions. Time-resolved terahertz spectroscopy (TRTS) measurements show that Ge:Au carrier lifetime is significantly higher than that in previously studied hyperdoped silicon systems. Furthermore, we find that lattice composition, sub-band-gap optical absorption, and carrier dynamics depend greatly on hyperdoping conditions. We use density functional theory (DFT) to model dopant distribution, electronic band structure, and optical absorption. These simulations help explain experimentally observed differences in optical and optoelectronic behavior across different samples. DFT modeling reveals that substitutional dopant incorporation has the lowest formation energy and leads to deep energy levels. In contrast, interstitial or dopant-vacancy complex incorporation yields shallower energy levels that do not contribute to sub-band-gap light absorption and have a small effect on charge carrier lifetimes. These results suggest that it is promising to tailor dopant incorporation sites of Ge:Au for SWIR photodetection applications.
PB Amer Physical Soc
SN 2331-7019
YR 2020
FD 2020-12-16
LK https://hdl.handle.net/20.500.14352/6774
UL https://hdl.handle.net/20.500.14352/6774
LA spa
NO Department of Defense (DoD)
NO National Defense Science and Engineering Graduate Fellowship (NDSEG) Program
NO Directed Energy Processing Society Graduate Fellowship
NO Ministerio de Ciencia, Innovación y Universidades
NO Gobierno regional de Madrid con los proyectos FEDER
NO US Air Force Office of Scientific Research
NO National Science Foundation
DS Docta Complutense
RD 18 abr 2025