skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Optical properties of ZnO/ZnS and ZnO/ZnTe heterostructures forphotovoltaic applications

Abstract

Although ZnO and ZnS are abundant, stable, environmentallybenign, their band gap energies (3.44 eV, 3.72 eV) are too large foroptimal photovoltaic efficiency. By using band-corrected pseudopotentialdensity-functional theory calculations, we study how the band gap,opticalabsorption, and carrier localization canbe controlled by formingquantum-well like and nanowire-based heterostructures ofZnO/ZnS andZnO/ZnTe. In the case of ZnO/ZnS core/shell nanowires, which can besynthesized using existing methods, we obtain a band gap of 2.07 eV,which corresponds to a Shockley-Quiesser efficiency limitof 23 percent.Based on these nanowire results, we propose that ZnO/ZnScore/shellnanowires can be used as photovoltaic devices with organic polymersemiconductors as p-channel contacts.

Authors:
; ; ;
Publication Date:
Research Org.:
Ernest Orlando Lawrence Berkeley NationalLaboratory, Berkeley, CA (US)
Sponsoring Org.:
USDOE Director. Office of Science. Basic EnergySciences
OSTI Identifier:
928786
Report Number(s):
LBNL-62616
R&D Project: K11704; BnR: KC0202030; TRN: US200811%%336
DOE Contract Number:
DE-AC02-05CH11231
Resource Type:
Journal Article
Resource Relation:
Journal Name: Nano Letters; Journal Volume: 7; Journal Issue: 8; Related Information: Journal Publication Date: 2007
Country of Publication:
United States
Language:
English
Subject:
14; 36; ABSORPTION; EFFICIENCY; OPTICAL PROPERTIES; ORGANIC POLYMERS; ZnO

Citation Formats

Schrier, Joshua, Demchenko, Denis O., Wang, Lin-Wang, and Alivisatos,A. Paul. Optical properties of ZnO/ZnS and ZnO/ZnTe heterostructures forphotovoltaic applications. United States: N. p., 2007. Web. doi:10.1021/nl071027k.
Schrier, Joshua, Demchenko, Denis O., Wang, Lin-Wang, & Alivisatos,A. Paul. Optical properties of ZnO/ZnS and ZnO/ZnTe heterostructures forphotovoltaic applications. United States. doi:10.1021/nl071027k.
Schrier, Joshua, Demchenko, Denis O., Wang, Lin-Wang, and Alivisatos,A. Paul. Tue . "Optical properties of ZnO/ZnS and ZnO/ZnTe heterostructures forphotovoltaic applications". United States. doi:10.1021/nl071027k. https://www.osti.gov/servlets/purl/928786.
@article{osti_928786,
title = {Optical properties of ZnO/ZnS and ZnO/ZnTe heterostructures forphotovoltaic applications},
author = {Schrier, Joshua and Demchenko, Denis O. and Wang, Lin-Wang and Alivisatos,A. Paul},
abstractNote = {Although ZnO and ZnS are abundant, stable, environmentallybenign, their band gap energies (3.44 eV, 3.72 eV) are too large foroptimal photovoltaic efficiency. By using band-corrected pseudopotentialdensity-functional theory calculations, we study how the band gap,opticalabsorption, and carrier localization canbe controlled by formingquantum-well like and nanowire-based heterostructures ofZnO/ZnS andZnO/ZnTe. In the case of ZnO/ZnS core/shell nanowires, which can besynthesized using existing methods, we obtain a band gap of 2.07 eV,which corresponds to a Shockley-Quiesser efficiency limitof 23 percent.Based on these nanowire results, we propose that ZnO/ZnScore/shellnanowires can be used as photovoltaic devices with organic polymersemiconductors as p-channel contacts.},
doi = {10.1021/nl071027k},
journal = {Nano Letters},
number = 8,
volume = 7,
place = {United States},
year = {Tue May 01 00:00:00 EDT 2007},
month = {Tue May 01 00:00:00 EDT 2007}
}
  • The electronic structure and optical properties of biaxial ZnO-ZnS heterostructure nanoribbons (NRs) have been investigated using x-ray absorption near-edge structures (XANES) and x-ray excited optical luminescence (XEOL). The XANES were recorded in total electron yield and wavelength-selected photoluminescence yield across the K- and L 3,2-edges of zinc and sulfur and the K-edge of oxygen. The XEOL from the NRs exhibit a very weak band-gap emission at 392 nm and two intense defect emissions at 491 and 531 nm. The synchrotron x-ray pulse (- 100 ps, 153 ns repetition rate) was used to track the optical decay dynamics from ZnO-ZnS NR,more » which can be described by two lifetimes (7.6 and 55 ns). Comparison with similar measurements for ZnO and ZnS nanowires reveals that the luminescence from ZnO-ZnS NRs was dominated by the ZnO component of the NR as the ZnS component contributes little. The implication of this observation is discussed.« less
  • Graphical abstract: The phase conversion of ZnS to highly crystalline hexagonal ZnO was done by heat treatment. - Highlights: • Phase change of cubic ZnS to hexagonal ZnO via heat treatment. • Band gap was found to decrease with increasing calcinations temperature. • ZnO samples have higher magnetic moment than ZnS. • Blocking Temperature of the samples is well above room temperature. • Maximum negative%MR with saturation value ∼38% was found for sample calcined at 600° C. - Abstract: The present work concentrates on the synthesis of cubic ZnS and hexagonal ZnO semiconducting nanoparticle from same precursor via co-precipitation method.more » The phase conversion of ZnS to highly crystalline hexagonal ZnO was done by heat treatment. From the analysis of influence of calcination temperature on the structural, optical and vibrational properties of the samples, an optimum temperature was found for the total conversion of ZnS nanoparticles to ZnO. Role of quantum confinement due to finite size is evident from the blue shift of the fundamental absorption in UV–vis spectra only in the ZnS nanoparticles. The semiconducting nature of the prepared samples is confirmed from the UV–vis, PL study and transport study. From the magnetic and transport studies, pure ZnO phase was found to be more prone to magnetic field.« less
  • Highlights: ► ZnS/ZnO quantum dots (QDs) were synthesized by controlled oxidation of ZnS nanoparticles. ► Interfacial heterostructure formation of ZnS/ZnO QDs is seen in HRTEM. ► Enormous enhancement of UV emission (∼10 times) in ZnS/ZnO QDs heterostructure is observed. ► Phonon confinement effect is seen in the Raman spectrum. -- Abstract: ZnS/ZnO quantum dots (QDs) were synthesized by controlled oxidation of ZnS nanoparticles. HRTEM image showed small nanocrystals of size 4 nm and the magnified image of single quantum dot shows interfacial heterostructure formation. The optical absorption spectrum shows a blue shift of 0.19 and 0.23 eV for ZnO andmore » ZnS QDs, respectively. This is due to the confinement of charge carries within the nanostructures. Enormous enhancement in UV emission (10 times) is reported which is attributed to interfacial heterostructure formation. Raman spectrum shows phonons of wurtzite ZnS and ZnO. Phonon confinement effect is seen in the Raman spectrum wherein LO phonon peaks of ZnS and ZnO are shifted towards lower wavenumber side and are broadened.« less
  • This paper studies the luminescence characteristics of the components of ZnTe-ZnSe hetero-structures obtained by liquid-phase epitaxy of ZnTe and SnSe substrates oriented in the (III) plane; the epitaxy was based on a solution-melt in metal (Sn, Bi). The influence of the metal melt and the technological conditions of crystal growing upon the luminescence properties of the ZnSe substrate is studied. The authors followed the changes in the ZnSe luminescence spectrum in each stage of the study. Typical photoluminescence spectra is shown of ZnSe single crystals which had been grown recently and annealed in liquid Zn. When ZnTe-ZnSe heterostructures are producedmore » by liquid phase epitaxy from solution melts in Bi and Sn, the radiative properties of ZnSe substrates do not change because disturbances of stoichiometry are prevented. The luminescence properties of ZnSe substrates which were subjected to annealing can be described by the concepts of annealing ZnSe with copper.« less
  • Zinc oxide films were produced by spray pyrolysis starting with aqueous solutions of ZnCl/sub 2/, ZnCl/sub 2/ plus H/sub 2/O/sub 2/, and Zn acetate, and structural, optical, electrical, and thermoelectrical properties of the deposited films were investigated. Highly transparent films with resistivity as low as 10/sup -3/ ..cap omega.. cm can be produced by suitable control of deposition procedures and by postdeposition annealing in hydrogen.