A Story Told by a Single Nanowire: Optical Properties of Wurtzite GaAs
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- 作者：Lyubomir Ahtapodov ; Jelena Todorovic ; Phillip Olk ; Terje Mj氓land ; Patrick Sl氓ttnes ; Dasa L. Dheeraj ; Antonius T. J. van Helvoort ; Bj酶rn-Ove Fimland ; Helge Weman
- 刊名：Nano Letters
- 出版年：2012
- 出版时间：December 12, 2012
- 年：2012
- 卷：12
- 期：12
- 页码：6090-6095
- 全文大小：379K
- 年卷期：v.12,no.12(December 12, 2012)
- ISSN：1530-6992
文摘
The optical properties of the wurtzite (WZ) GaAs crystal phase found in nanowires (NWs) are a highly controversial topic. Here, we study high-quality pure WZ GaAs/AlGaAs core鈥搒hell NWs grown by Au-assisted molecular beam epitaxy (MBE) with microphotoluminescence spectroscopy (渭-PL) and (scanning) transmission electron microscopy on the very same single wire. We determine the room temperature (294 K) WZ GaAs bandgap to be 1.444 eV, which is 20 meV larger than in zinc blende (ZB) GaAs, and show that the free exciton emission at 15 K is at 1.516 eV. On the basis of time- and temperature-resolved 渭-PL results, we propose a 螕8 conduction band symmetry in WZ GaAs. We suggest a method for quantifying the optical quality of NWs, taking into consideration the difference between the room and low temperature integrated PL intensity, and demonstrate that Au-assisted GaAs/AlGaAs core鈥搒hell NWs can have high PL brightness up to room temperature.