Excitonic stimulated emission from MgxZn1-xO films due to enhanced exciton binding energy

• Fujii, Shusuke

• Adachi, Yutaka

• 内野, 隆司

抄録

We report synthesis and excitonic emission properties of high-quality micrometer-thick MgxZn1-xO films (x = 0.04 and 0.10) grown on a-sapphire substrates by pulsed laser deposition. The band gap E-g values of the x = 0.04 and 0.10 samples have been shown to be larger than that of pure ZnO by ∼0.1 and ∼0.3 eV, respectively. From the investigations of the stimulated emission due to the exciton-exciton (ex-ex) scattering process at 3 K, the exciton binding energies E-b of the x = 0.04 and 0.10 samples are determined to be 80 ± 5 and 120 ± 10 meV, respectively, which are substantially larger than that of pure ZnO (Eb = 60 meV). The present observation demonstrates that E-b of ZnO-based materials can be increased to 100% by controlling the synthetic and alloying conditions. Purely excitonic stimulated emissions are observed in the temperature range from 3 to 300 K without showing any symptoms of electron-hole plasma emission. The mechanism of the optical gain changes from the ex-ex to ex-electron (ex-el) scattering process at 200 and 250 K for the x = 0.04 and 0.10 samples, respectively, with increasing temperature. We argue that the enhancement of E-b occurs as a consequence of a complex, combined effect of Mg addition on the effective electron/hole masses and the dielectric constant of the MgxZn1-xO films.

収録刊行物

• Physical Review B

  Physical Review B 102 (7), 075204-075204, 2020-08-06

  American Physical Society (APS)

詳細情報

• CRID: 1050575520345664640
• NII論文ID: 120006886638
• NII書誌ID: AA11187113
• ISSN: 24699969
• ISSN: 24699950
• HANDLE: 20.500.14094/90007450
• 本文言語コード: en
• 資料種別: journal article
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