High throughput optimizations of alloy and doped films based on ZnO and parallel synthesis of ZnO/MgxZn1-xO quantum wells using combinatorial laser MBE towards ultraviolet laser

Akira Ohtomo, Takayuki Makino, Kentaro Tamura, Yuji Matsumoto, Yusaburo Segawa, Zikang Tang, George K.L. Wong, Hideomi Koinuma, Masashi Kawasaki

Research output: Contribution to journalConference articlepeer-review

11 Citations (Scopus)

Abstract

We report high-throughput optimizations for various material parameters of MgxZn1-xO and Zn1-xCdxO alloy films, Al-doped ZnO films, MgxZn1-xO/ZnO single quantum wells and superlattice structures with using combinatorial laser MBE (CL-MBE). Combinatorial chips including nine thin film pixels were grown on lattice-matched ScAlMgO4 (0001) substrates by switching the mask patterns and targets during pulsed laser deposition. For alloy experiments, two chips (two runs) provided us with complete and systematic understanding of the band gap in a range from 3.0 to 3.6 eV. An Al-doped chip revealed systematic variation of the conductivity from 3 to 2 × 103 Scm-1. A single quantum well chip showed clear systematic variation of photoluminescence peak energy as a function of well layer thickness. Two superlattice chips showed clear systematics on the quantum sub-band levels in absorption spectra even at room temperature, giving all desired information being useful for designing an efficient active layer in possible ultraviolet light emitting devices. The excitonic stimulated emissions could be observed even at very low optical pumping at room temperature. The threshold excitation intensity changed in a range of 11-40 kW/cm2 and the emission energy can be tuned between 3.2 and 3.4 eV, depending on the well layer thickness and/or the Mg content in the barrier layers. The excitonic stimulated emission could be observed up to 100°C and a characteristic temperature was as high as 87 K for the best sample optimized by the combinatorial approach using only 8 deposition runs carried out in a week.

Original languageEnglish
Pages (from-to)70-81
Number of pages12
JournalProceedings of SPIE - The International Society for Optical Engineering
Volume3941
Publication statusPublished - 2000 Jan 1
Externally publishedYes
EventCombinatorial and Composition Spread Techniques in Materials and Devices Development - San Jose, CA, USA
Duration: 2000 Jan 262000 Jan 26

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

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