Systematic examination of carrier polarity in composition spread ZnO thin films codoped with Ga and N

A. Tsukazaki, H. Saito, K. Tamura, M. Ohtani, H. Koinuma, M. Sumiya, S. Fuke, T. Fukumura, M. Kawasaki

Research output: Contribution to journalArticlepeer-review

93 Citations (Scopus)

Abstract

We have grown high-crystallinity ZnO thin films on lattice-matched ScAlMgO4 substrates by pulsed-laser deposition with doping donor (Ga) and acceptor (N) simultaneously. Alternating ablation of ceramics with concentrated Ga addition and highly pure single crystal targets yielded in a controlled Ga concentration (CGa) in a wide range of 10 18-1020cm-3 with minimal contamination of undesired impurities such as Al and Si. The use of the originally developed temperature-gradient method, where controlled and continuous gradient of the growth temperature is given to the single substrate with a range of about 50-200°C, results in a continuous spread of N concentration (CN) in a controlled fashion. Therefore, the ratio of CN/CGa can be varied continuously in a wide range for each film, assuring that a region satisfying p-type codoping condition predicted by T. Yamamoto and H. K. Yoshida [Jpn. J. Appl. Phys., Part 2 38, L166 (1999)] is included in the sample. The electrical properties were measured for over thousand specimens of lithographically patterned Hall bars without observing any sign of p-type conduction.

Original languageEnglish
Pages (from-to)235-237
Number of pages3
JournalApplied Physics Letters
Volume81
Issue number2
DOIs
Publication statusPublished - 2002 Jul 8

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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