Enhanced near-infrared responsivity of silicon photodetector by the impurity photovoltaic effect

Yuan, Jiren; Huang, Haibin; Deng, Xiaobing; Liang, Xiaojun; Zhou, Naigen; Zhou, Lang

doi:10.1088/1674-1056/24/4/048501

Cited by 2 publications

(1 citation statement)

References 14 publications

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“…The impurity photovoltaic (IPV) effect has attracted considerable attention since solar cells employing it can additionally absorb the sub-bandgap photons and thus enhance the photogenerated current. [1][2][3][4][5][6][7][8] The principle of the IPV effect is to introduce an energy level within the material bandgap by doping. The energy level acts as a stepping stone and causes photons with energies less than the bandgap energy to be collected via a two-step absorption mechanism, in which a sub-bandgap photon excites an electron from the valence band to the impurity level and then another sub-bandgap photon pumps it from there to the conduction band.…”

Section: Introductionmentioning

confidence: 99%

Photoemission cross section: A critical parameter in the impurity photovoltaic effect

et al. 2017

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A numerical study has been conducted to explore the role of photoemission cross sections in the impurity photovoltaic (IPV) effect for silicon solar cells doped with indium. The photovoltaic parameters (short-circuit current density, opencircuit voltage, and conversion efficiency) of the IPV solar cell were calculated as functions of variable electron and hole photoemission cross sections. The presented results show that the electron and hole photoemission cross sections play critical roles in the IPV effect. When the electron photoemission cross section is < 10 −20 cm 2 , the conversion efficiency η of the IPV cell always has a negative gain (∆η < 0) if the IPV impurity is introduced. A large hole photoemission cross section can adversely impact IPV solar cell performance. The combination of a small hole photoemission cross section and a large electron photoemission cross section can achieve higher conversion efficiency for the IPV solar cell since a large electron photoemission cross section can enhance the necessary electron transition from the impurity level to the conduction band and a small hole photoemission cross section can reduce the needless sub-bandgap absorption. It is concluded that those impurities with small (large) hole photoemission cross section and large (small) electron photoemission cross section, whose energy levels are near the valence (or conduction) band edge, may be suitable for use in IPV solar cells. These results may help in judging whether or not an impurity is appropriate for use in IPV solar cells according to its electron and hole photoemission cross sections.

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Section: Introductionmentioning

confidence: 99%

Photoemission cross section: A critical parameter in the impurity photovoltaic effect

et al. 2017

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A method of wall clutter removal for through-wall radar based on entropy of expanded antenna source

Li¹,

Cai²,

Chen³

et al. 2015

Acta Phys. Sin.

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Strong front wall clutter has serious impacts on the target detection and imaging in the through-wall radar (TWR) system. A method of robust wall clutter suppression based on the entropy of an expanded antenna source for ultra-wide-band through-wall radar is presented in this paper. The model of TWR scenario consists of four layers. Assume that the first and the third layers are air space, while the second and the fourth layers are composed of uniform flat concrete wall. The circular target, assumed to be a perfect electric conductor, is located in the third layer. Along the measurement line which is parallel to the front wall, the transceiver antenna scans uniformly. The echo signals that come from the target and walls are processed into discrete data at first, so that the calculation of probability space is subsequently implemented and the discrete data are expanded as well. And then the entropy of the expanded data that contain robust wall clutter and echo of target is calculated. Taking into consideration the amplitude of target signal varying in each scan, while that of clutter signal is not, it is evident that the entropy can be utilized to discriminate the signals between the target and wall. According to the difference between the entropy of the wall clutter and that of the target, a certain threshold can be set and the optimum tolerance threshold is adaptively selected on the basis of target-to-clutter ratio. With the optimum tolerance threshold, process of clutter suppression is conducted. Finally, back projection is employed for imaging of target. In this paper, data of through-wall radar for simulation are provided by GprMax2D/3D, based on the finite difference-time domain methsd. The clutter suppression and imaging are separately conducted by the method based on data entropy and the method proposed in this paper. Comparing the results of simulations, it is shown that the gain of target-to-clutter ratio for the former is 15.51 dB, and that for the latter is 19.74 dB. It is obvious that the proposed method can provide imaging with higher quality for the same measurement, and it requires fewer scans with the same quality of imaging as well. Computational complexity of the proposed method and the method based on entropy can be expressed as O(M NL) and O(M N) , respectively

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Enhanced near-infrared responsivity of silicon photodetector by the impurity photovoltaic effect

Cited by 2 publications

References 14 publications

Photoemission cross section: A critical parameter in the impurity photovoltaic effect

Photoemission cross section: A critical parameter in the impurity photovoltaic effect

A method of wall clutter removal for through-wall radar based on entropy of expanded antenna source

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