Charge confinement and thermal transport processes in modulation-doped epitaxial crystals lacking lattice interfaces

Elizabeth Radue, Evan L. Runnerstrom, Kyle P. Kelley, Christina M. Rost, Brian F. Donovan, Everett D. Grimley, James M. Lebeau, Jon-Paul Maria, Patrick E. Hopkins

Research output: Contribution to journalArticle

Abstract

Heterogeneous nanosystems offer a robust potential for manipulating various functional material properties, beyond those possible from their individual constituent materials. We demonstrate the formation of a class of materials with a homogeneous lattice but spatially heterogeneous electrical functionality; specifically, we develop epitaxial modulation-doped thin films in which the spatial separation of electronic charge densities is achieved without perturbing the parent crystal's compositional or structural homogeneity. Unlike the previous realizations of modulation doping in crystals, our materials demonstrate periodic layering of spatially segregated, varying electronically donor-doped regions in a single compositionally and structurally homogenous single-crystalline lattice. We demonstrate the formation of "modulation-doped epitaxial crystals" (MoDECs) using alternating layers of doped cadmium oxide, and the ability to spatially confine regions of variable carrier concentration via low potential-energy barriers in a spatially homogeneous, epitaxial crystal with a chemically and structurally homogenous lattice (i.e., no chemical or structural lattice interfaces). The low potential energy that confines electrons within the doped layers coupled with the crystalline nature of the MoDECs and lack of lattice interfaces presents a platform to study the electron thermal boundary resistances at low-energy electronic barriers. We find that the electron interfacial density does not impede thermal conductivity, despite evidence that the doped layers retain their carrier concentrations. Thus, the negligible thermal boundary resistances at the electronic interfaces result in the thermal conductivities of the MoDECs being related to only a series resistance sum of the thermal resistances of each of the individual layers, with no thermal resistances from the electronic boundaries that maintain charge separation. This is in stark contrast with other nanoscale multilayer materials, where thermal boundary resistances at the internal material interfaces reduce the thermal conductivity of the multilayer compared to that of the parent materials. The ability to modulation dope epitaxially grown films with no structural heterogeneity in the lattice will further enable unique platforms for mid-IR photonics, such as hyperbolic metamaterials, optical filters with spatially discrete optical absorption, or energy harvesting based on charge injection across modulation-doped interfaces.

Original languageEnglish (US)
Article number032201
JournalPhysical Review Materials
Volume3
Issue number3
DOIs
StatePublished - Mar 29 2019

Fingerprint

doped crystals
crystal lattices
Crystal lattices
Modulation
modulation
Crystals
thermal conductivity
Thermal conductivity
thermal resistance
electronics
Potential energy
Heat resistance
platforms
Carrier concentration
potential energy
Electrons
Multilayers
modulation doping
crystals
electrons

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Physics and Astronomy (miscellaneous)

Cite this

Radue, E., Runnerstrom, E. L., Kelley, K. P., Rost, C. M., Donovan, B. F., Grimley, E. D., ... Hopkins, P. E. (2019). Charge confinement and thermal transport processes in modulation-doped epitaxial crystals lacking lattice interfaces. Physical Review Materials, 3(3), [032201]. https://doi.org/10.1103/PhysRevMaterials.3.032201
Radue, Elizabeth ; Runnerstrom, Evan L. ; Kelley, Kyle P. ; Rost, Christina M. ; Donovan, Brian F. ; Grimley, Everett D. ; Lebeau, James M. ; Maria, Jon-Paul ; Hopkins, Patrick E. / Charge confinement and thermal transport processes in modulation-doped epitaxial crystals lacking lattice interfaces. In: Physical Review Materials. 2019 ; Vol. 3, No. 3.
@article{464de8710892430083d5a378228804ed,
title = "Charge confinement and thermal transport processes in modulation-doped epitaxial crystals lacking lattice interfaces",
abstract = "Heterogeneous nanosystems offer a robust potential for manipulating various functional material properties, beyond those possible from their individual constituent materials. We demonstrate the formation of a class of materials with a homogeneous lattice but spatially heterogeneous electrical functionality; specifically, we develop epitaxial modulation-doped thin films in which the spatial separation of electronic charge densities is achieved without perturbing the parent crystal's compositional or structural homogeneity. Unlike the previous realizations of modulation doping in crystals, our materials demonstrate periodic layering of spatially segregated, varying electronically donor-doped regions in a single compositionally and structurally homogenous single-crystalline lattice. We demonstrate the formation of {"}modulation-doped epitaxial crystals{"} (MoDECs) using alternating layers of doped cadmium oxide, and the ability to spatially confine regions of variable carrier concentration via low potential-energy barriers in a spatially homogeneous, epitaxial crystal with a chemically and structurally homogenous lattice (i.e., no chemical or structural lattice interfaces). The low potential energy that confines electrons within the doped layers coupled with the crystalline nature of the MoDECs and lack of lattice interfaces presents a platform to study the electron thermal boundary resistances at low-energy electronic barriers. We find that the electron interfacial density does not impede thermal conductivity, despite evidence that the doped layers retain their carrier concentrations. Thus, the negligible thermal boundary resistances at the electronic interfaces result in the thermal conductivities of the MoDECs being related to only a series resistance sum of the thermal resistances of each of the individual layers, with no thermal resistances from the electronic boundaries that maintain charge separation. This is in stark contrast with other nanoscale multilayer materials, where thermal boundary resistances at the internal material interfaces reduce the thermal conductivity of the multilayer compared to that of the parent materials. The ability to modulation dope epitaxially grown films with no structural heterogeneity in the lattice will further enable unique platforms for mid-IR photonics, such as hyperbolic metamaterials, optical filters with spatially discrete optical absorption, or energy harvesting based on charge injection across modulation-doped interfaces.",
author = "Elizabeth Radue and Runnerstrom, {Evan L.} and Kelley, {Kyle P.} and Rost, {Christina M.} and Donovan, {Brian F.} and Grimley, {Everett D.} and Lebeau, {James M.} and Jon-Paul Maria and Hopkins, {Patrick E.}",
year = "2019",
month = "3",
day = "29",
doi = "10.1103/PhysRevMaterials.3.032201",
language = "English (US)",
volume = "3",
journal = "Physical Review Materials",
issn = "2475-9953",
publisher = "American Physical Society",
number = "3",

}

Radue, E, Runnerstrom, EL, Kelley, KP, Rost, CM, Donovan, BF, Grimley, ED, Lebeau, JM, Maria, J-P & Hopkins, PE 2019, 'Charge confinement and thermal transport processes in modulation-doped epitaxial crystals lacking lattice interfaces', Physical Review Materials, vol. 3, no. 3, 032201. https://doi.org/10.1103/PhysRevMaterials.3.032201

Charge confinement and thermal transport processes in modulation-doped epitaxial crystals lacking lattice interfaces. / Radue, Elizabeth; Runnerstrom, Evan L.; Kelley, Kyle P.; Rost, Christina M.; Donovan, Brian F.; Grimley, Everett D.; Lebeau, James M.; Maria, Jon-Paul; Hopkins, Patrick E.

In: Physical Review Materials, Vol. 3, No. 3, 032201, 29.03.2019.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Charge confinement and thermal transport processes in modulation-doped epitaxial crystals lacking lattice interfaces

AU - Radue, Elizabeth

AU - Runnerstrom, Evan L.

AU - Kelley, Kyle P.

AU - Rost, Christina M.

AU - Donovan, Brian F.

AU - Grimley, Everett D.

AU - Lebeau, James M.

AU - Maria, Jon-Paul

AU - Hopkins, Patrick E.

PY - 2019/3/29

Y1 - 2019/3/29

N2 - Heterogeneous nanosystems offer a robust potential for manipulating various functional material properties, beyond those possible from their individual constituent materials. We demonstrate the formation of a class of materials with a homogeneous lattice but spatially heterogeneous electrical functionality; specifically, we develop epitaxial modulation-doped thin films in which the spatial separation of electronic charge densities is achieved without perturbing the parent crystal's compositional or structural homogeneity. Unlike the previous realizations of modulation doping in crystals, our materials demonstrate periodic layering of spatially segregated, varying electronically donor-doped regions in a single compositionally and structurally homogenous single-crystalline lattice. We demonstrate the formation of "modulation-doped epitaxial crystals" (MoDECs) using alternating layers of doped cadmium oxide, and the ability to spatially confine regions of variable carrier concentration via low potential-energy barriers in a spatially homogeneous, epitaxial crystal with a chemically and structurally homogenous lattice (i.e., no chemical or structural lattice interfaces). The low potential energy that confines electrons within the doped layers coupled with the crystalline nature of the MoDECs and lack of lattice interfaces presents a platform to study the electron thermal boundary resistances at low-energy electronic barriers. We find that the electron interfacial density does not impede thermal conductivity, despite evidence that the doped layers retain their carrier concentrations. Thus, the negligible thermal boundary resistances at the electronic interfaces result in the thermal conductivities of the MoDECs being related to only a series resistance sum of the thermal resistances of each of the individual layers, with no thermal resistances from the electronic boundaries that maintain charge separation. This is in stark contrast with other nanoscale multilayer materials, where thermal boundary resistances at the internal material interfaces reduce the thermal conductivity of the multilayer compared to that of the parent materials. The ability to modulation dope epitaxially grown films with no structural heterogeneity in the lattice will further enable unique platforms for mid-IR photonics, such as hyperbolic metamaterials, optical filters with spatially discrete optical absorption, or energy harvesting based on charge injection across modulation-doped interfaces.

AB - Heterogeneous nanosystems offer a robust potential for manipulating various functional material properties, beyond those possible from their individual constituent materials. We demonstrate the formation of a class of materials with a homogeneous lattice but spatially heterogeneous electrical functionality; specifically, we develop epitaxial modulation-doped thin films in which the spatial separation of electronic charge densities is achieved without perturbing the parent crystal's compositional or structural homogeneity. Unlike the previous realizations of modulation doping in crystals, our materials demonstrate periodic layering of spatially segregated, varying electronically donor-doped regions in a single compositionally and structurally homogenous single-crystalline lattice. We demonstrate the formation of "modulation-doped epitaxial crystals" (MoDECs) using alternating layers of doped cadmium oxide, and the ability to spatially confine regions of variable carrier concentration via low potential-energy barriers in a spatially homogeneous, epitaxial crystal with a chemically and structurally homogenous lattice (i.e., no chemical or structural lattice interfaces). The low potential energy that confines electrons within the doped layers coupled with the crystalline nature of the MoDECs and lack of lattice interfaces presents a platform to study the electron thermal boundary resistances at low-energy electronic barriers. We find that the electron interfacial density does not impede thermal conductivity, despite evidence that the doped layers retain their carrier concentrations. Thus, the negligible thermal boundary resistances at the electronic interfaces result in the thermal conductivities of the MoDECs being related to only a series resistance sum of the thermal resistances of each of the individual layers, with no thermal resistances from the electronic boundaries that maintain charge separation. This is in stark contrast with other nanoscale multilayer materials, where thermal boundary resistances at the internal material interfaces reduce the thermal conductivity of the multilayer compared to that of the parent materials. The ability to modulation dope epitaxially grown films with no structural heterogeneity in the lattice will further enable unique platforms for mid-IR photonics, such as hyperbolic metamaterials, optical filters with spatially discrete optical absorption, or energy harvesting based on charge injection across modulation-doped interfaces.

UR - http://www.scopus.com/inward/record.url?scp=85064173329&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85064173329&partnerID=8YFLogxK

U2 - 10.1103/PhysRevMaterials.3.032201

DO - 10.1103/PhysRevMaterials.3.032201

M3 - Article

AN - SCOPUS:85064173329

VL - 3

JO - Physical Review Materials

JF - Physical Review Materials

SN - 2475-9953

IS - 3

M1 - 032201

ER -