The ITO/Si heterojunction has been studied as a solar cell longtime ago, but seldom done on the lateral photovoltaic effect (LPE). In this paper, we reported a new finding of lateral photovoltaic effect (LPE) in the ITO/Si(n) heterojunctions. The ITO films were prepared directly on the n-type single crystal Si substrate with different thicknesses by magnetron reactive sputtering technology. When we measured the lateral photovoltages in the ITO/Si structures as a function of laser position under illumination of different laser powers and different laser wavelengths, it was found that the LPE increased with both laser power and laser wavelength, which can be ascribed to the increased number of electron-hole pairs resulting from the increased laser power for a constant laser wavelength or the increased laser wavelength for a constant laser power. Moreover, the position sensitivity decreased dramatically with increasing the thickness of ITO thin films, but the nonlinearity seems to be improved gradually, both of which can be successfully explained by the increased carrier diffusion length induced by the decreased resistivity of ITO layer. The ITO/Si(n) heterojunction possesses good position sensitivity and suitable nonlinearity simultaneously when the thickness of ITO layer is 15 nm. Our results may provide important insight that one can obtain a suitable LPE in the ITO/Si(n) heterojunction with higher position sensitivity and lower nonlinearity by controlling the thickness of the ITO thin films, and also suggest that the ITO/Si(n) heterojunction is a potential candidate for developing novel and multifunctional optical sensors.
河北省青年拔尖人才支持计划
国家自然科学基金(51372064)
河北省高等学校科学技术研究重点项目(ZD2016036)
河北大学杰出青年基金项目
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Figure 1
(Color online) (a)
Figure 2
(Color online) (a) Diagram of energy-band for ITO/Si structure; (b) schematic of holes transition and diffusion under a spot illumination.
Figure 3
(Color online) (a) LPVs as a function of laser position with different laser power; (b) the position sensitivity and nonlinearity as a function of laser power.
Figure 4
(Color online) (a) Position Sensitivity as a function of laser power as well as wavelength. The LPVs of different wavelengths at a fixed laser power of 5 mW. (b) the nonlinearity as a function of laser power as well as wavelength.
Figure 5
(Color online) (a) LPVs as a function of laser position with several different thickness of ITO films; (b) the positon sensitivity and nonlinearity as a function of film thickness.
|
薄膜厚度 (nm) |
电阻率 (10–6 |
|
7.5 |
4.29 |
|
15 |
2.60 |
|
37.5 |
2.51 |
|
75 |
1.78 |
|
150 |
1.61 |
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