Direct growth of tungsten disulfide on gallium nitride and the photovoltaic characteristics of the heterojunctions
Direct growth of tungsten disulfide on gallium nitride and the photovoltaic characteristics of the heterojunctions
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DOI：
10.1088/1361-6641/abd18f
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发表时间：
2020-12
影响因子：
1.9
通讯作者：
Y. Wen;Rousan Debbarma;M. Rasul;R. Shahbazian‐Yassar;V. Berry;J. Shi
中科院分区：
文献类型：
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作者：
Y. Wen;Rousan Debbarma;M. Rasul;R. Shahbazian‐Yassar;V. Berry;J. Shi
在3D宽带隙半导体顶部使用2D纳米材料构建的光伏器件能够在紧邻耗尽区（上方几个原子）的前表面上实现货车霍韦奇异性诱导的增强光吸收。这里，通过低压化学气相沉积在n-氮化镓（GaN）和p-GaN上直接生长从单层到几层的二硫化钨（WS 2）薄层。WS 2生长的条件进行了优化，以获得更大的GaN衬底覆盖率。采用共焦拉曼光谱和X射线光电子能谱对WS 2薄膜进行了表征。利用紫外光电子能谱（UV-photoelectron spectroscopy，XPS）研究了WS 2在GaN上的能带结构。然后制备了WS 2/GaN异质结光伏器件。进行电流密度-电压（J-V）测试以说明电性能。该器件的开路电压为0.53 mV，短路电流密度为60 µA cm−2，比WS 2/Si太阳能电池高85%。外量子效率被测量为接近60%的红色和红外，并在紫色区域超过50%。
Photovoltaic device construct with a 2D nanomaterial atop a 3D wide bandgap semiconductor enables van Hove singularity induced enhanced light absorption on the front surface in close proximity (few atoms above) to the depletion region. Here, thin layers of tungsten disulfide (WS2) varying from mono to few layers were grown directly on both n-gallium nitride (GaN) and p-GaN via low pressure chemical vapor deposition. The conditions for WS2 growth were optimized for a larger coverage of the GaN substrate. The WS2 film was characterized using confocal Raman spectroscopy and x-ray photoelectron spectroscopy. Ultraviolet photoelectron spectroscopy measurement was conducted to elucidate the electronic band structures of WS2 on top of GaN. Afterwards, WS2/GaN heterojunction photovoltaic devices were fabricated. The current density–voltage (J–V) tests were conducted to illustrate the electrical performance. The device showed an open circuit voltage of 0.53 mV and a short circuit current density of 60 µA cm−2, 85% higher than that of a WS2/Si solar cell. An external quantum efficiency was measured to be near 60% for red and infrared, and above 50% in the violet region.