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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-23 18:10 |
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Conference: Bucharest University Faculty of Physics 2017 Meeting
Section: Solid State Physics and Materials Science
Title:
Increasing efficiency of p-n junction cooling device
Authors:
Stefan DOMOKOS (1), Stefan-Eduard DOMOKOS (1)
Affiliation:
1) DOMOKOS E. STEFAN PFA, Buzau, Romania
E-mail
sqdomokos@yahoo.com
Keywords:
p-n junction cooling device
Abstract:
It was shown that the InGaN LED with 20 μm diameter has a greater emitted power density than the greater diameter LED [1]. Cooling this LED with p-n junction can be increased the current density and the emitted power density for high resolution panels. Several p-n junctions with smaller lengths than that of the LED, three times of the length of the depletion layer, and the widths equal with the diameter of the LED parallel connected are producing a greater current and a greater cooling efficiency. Also increasing the distance between the LED's and using fins array on the substrate is increasing the cooling by natural convection [2]. By experimental results was obtained that the space-charge-limited current in thin film semiconductor in which the thickness is much smaller than the length the current is inversely proportional to the square of the electrode distance [3]. This result was confirmed by theoretical results [4]. In the cooling device can be used thin film p-n junction because it must be heated in all volume and its length can be small and is resulting the increase of the current as the effect of the above presented property. Recently it was shown that the space-charge-limited current in thin films is proportional with the dielectric constant of the surroundings [5]. Also nanowires presented in [5] can be deposited and parallel connected for cooling device. In an p-type semiconductor when one side is heated the generated holes, in greater concentration than the free electrons, diffuse to the cold side due to the concentration difference as the positive ions in the paper [6]. Then is produced an electric field which is moving the thermally generated free electrons from the heated side to the cold side in the external circuit.
References:
[1] Gong, Zheng, Jin, Shirong, Chen, Yujie, McKendry, Jonathan, Massoubre, David, Watson, Ian M., Gu, Erdan, and Dawson, Martin D., Size-dependent light output, spectral shift, and self-heating of 400 nm InGaN light-emitting diodes, J. Appl. Phys. 107, 013103 (2010).
[2] Fang, Shiwei, Wang, Weibiao, Liang, Jingqiu, Liang, Zhongzhu, Qin, Yuxin, and Lv, Jinguang, Heat dissipation analysis of bendable AlGaInP micro-LED arrays, AIP Advances 7, 015209 (2017).
[3] Polke, M., Stuke, J., and Vinariky, E., phys. stat. sol. 3, 1885 (1963).
[4] Guerst, J. A., Theory of Space-Charge-Limited Currents in Thin Semiconductir Layers, phys. stat. sol. 15, 107 (1966).
[5] Alagha, S., Shik, A., Ruda, H. E., Saveliev, I., Kavanagh, K. L., and Watkins, S. P., Space-charge-limited current in nanowires, J. Appl. Phys. 121, 174301 (2017).
[6] The world's first heat-driven transistor, Solis State Technology The Pulse, January 31, 2017.
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