Photoluminescence Mapping and Time-Domain Thermo-Photoluminescence for Rapid Imaging and Measurement of Thermal Conductivity of Boron Arsenide

Shuai Yue, Geethal Amila Gamage, Mohammadjavad Mohebinia, David Mayerich, Vishal Talari, Yu Deng, Fei Tian, Shen-Yu Dai, Haoran Sun, Viktor G. Hadjiev, Wei Zhang, Guoying Feng, Jonathan Hu, Dong Liu, Zhiming Wang, Zhifeng Ren and Jiming Bao

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Oct 18, 2019
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Received Date: 25th September 19

Cubic boron arsenide (BAs) is attracting greater attention due to the recent experimental demonstration of ultrahigh thermal conductivityk above 1000 W/m·K. However, its bandgap has not been settled and a simple yet effective method to probe its crystal quality is missing. Furthermore, traditional k measurement methods are destructive and time consuming, thus they cannot meet the urgent demand for fast screening of high k materials. After we experimentally established 1.82 eV as the indirect bandgap of BAs and observed room-temperature band-edge photoluminescence, we developed two new optical techniques that can provide rapid and non-destructive characterization of k with little sample preparation: photoluminescence mapping (PL-mapping) and time-domain thermo-photoluminescence (TDTP). PL-mapping provides nearly real-time image of crystal quality and k over mm-sized crystal surfaces; while TDTP allows us to pick up any spot on the sample surface and measure its k using nanosecond laser pulses. These new techniques reveal that the apparent single crystals are not only non-uniform in k, but also are made of domains of very distinct k. Because PL-mapping and TDTP are based on the band-edge PL and its dependence on temperature, they can be applied to other semiconductors, thus paving the way for rapid identification and development of high-k semiconducting materials.

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This is an abstract of a preprint hosted on an independent third party site. It has not been peer reviewed but is currently under consideration at Nature Communications.

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