Band alignment of epitaxial ZnS/Zn3P2 heterojunctions

Jeffrey P. Bosco, Steven B. Demers, Gregory M. Kimball, Nathan S Lewis, Harry A. Atwater

Research output: Contribution to journalArticle

21 Citations (Scopus)

Abstract

The energy-band alignment of epitaxial zb-ZnS(001)/α-Zn 3P2(001) heterojunctions has been determined by measurement of shifts in the phosphorus 2p and sulfur 2p core-level binding energies for various thicknesses (0.6-2.2 nm) of ZnS grown by molecular beam epitaxy on Zn3P2. In addition, the position of the valence-band maximum for bulk ZnS and Zn3P2 films was estimated using density functional theory calculations of the valence-band density-of-states. The heterojunction was observed to be type I, with a valence-band offset, ΔEV, of -1.19 ± 0.07 eV, which is significantly different from the type II alignment based on electron affinities that is predicted by Anderson theory. n+-ZnS/p-Zn3P 2 heterojunctions demonstrated open-circuit voltages of >750 mV, indicating passivation of the Zn3P2 surface due to the introduction of the ZnS overlayer. Carrier transport across the heterojunction devices was inhibited by the large conduction-band offset, which resulted in short-circuit current densities of 0.1 mA cm-2 under 1 Sun simulated illumination. Hence, constraints on the current density will likely limit the direct application of the ZnS/Zn3P2 heterojunction to photovoltaics, whereas metal-insulator-semiconductor structures that utilize an intrinsic ZnS insulating layer appear promising.

Original languageEnglish
Article number093703
JournalJournal of Applied Physics
Volume112
Issue number9
DOIs
Publication statusPublished - Nov 1 2012

Fingerprint

heterojunctions
alignment
valence
current density
heterojunction devices
MIS (semiconductors)
short circuit currents
electron affinity
open circuit voltage
passivity
energy bands
phosphorus
conduction bands
sun
sulfur
molecular beam epitaxy
binding energy
illumination
density functional theory
shift

ASJC Scopus subject areas

  • Physics and Astronomy(all)

Cite this

Bosco, J. P., Demers, S. B., Kimball, G. M., Lewis, N. S., & Atwater, H. A. (2012). Band alignment of epitaxial ZnS/Zn3P2 heterojunctions. Journal of Applied Physics, 112(9), [093703]. https://doi.org/10.1063/1.4759280

Band alignment of epitaxial ZnS/Zn3P2 heterojunctions. / Bosco, Jeffrey P.; Demers, Steven B.; Kimball, Gregory M.; Lewis, Nathan S; Atwater, Harry A.

In: Journal of Applied Physics, Vol. 112, No. 9, 093703, 01.11.2012.

Research output: Contribution to journalArticle

Bosco, JP, Demers, SB, Kimball, GM, Lewis, NS & Atwater, HA 2012, 'Band alignment of epitaxial ZnS/Zn3P2 heterojunctions', Journal of Applied Physics, vol. 112, no. 9, 093703. https://doi.org/10.1063/1.4759280
Bosco, Jeffrey P. ; Demers, Steven B. ; Kimball, Gregory M. ; Lewis, Nathan S ; Atwater, Harry A. / Band alignment of epitaxial ZnS/Zn3P2 heterojunctions. In: Journal of Applied Physics. 2012 ; Vol. 112, No. 9.
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