Probing photoelectric characteristics of graphene
碩士 === 國立交通大學 === 電子物理系所 === 102 === In this experiment, we probe into photocurrent of graphene devices and graphene/PbS thin film devices. Graphene flakes were made by mechanical exfoliation and PbS thin films were deposited by thermal evaporation. Due to its feature of a gapless semiconducto...
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ndltd-TW-102NCTU54290312015-10-14T00:18:21Z http://ndltd.ncl.edu.tw/handle/15755436008357435322 Probing photoelectric characteristics of graphene 探討石墨烯與其表面蒸鍍硫化鉛薄膜 Chen, Chau-Bi 陳喬弼 碩士 國立交通大學 電子物理系所 102 In this experiment, we probe into photocurrent of graphene devices and graphene/PbS thin film devices. Graphene flakes were made by mechanical exfoliation and PbS thin films were deposited by thermal evaporation. Due to its feature of a gapless semiconductor, graphene does not exhibit considerable photocurrent effects. The photocurrent of graphene flakes is about 36 nA and the enhancement ratio due to blue light excitation is 1.88 % at 80 K. In contrast, the PbS deposited graphene flakes may show higher photocurrent. It is argued that, after light illumination, the graphene is p-type doped. It implies that only holes transport to graphene after the generation of electron-hole pairs in PbS by light illumination. Therefore, the photocurrent is strongly dependent on the gating field. Though it does not show visible photoresponsivity at 300 K, the photoresponsivity increases largely at 80 K. When the gate biases are applied at -35 V and 35 V, the enhancement ratios raise up to 15.77 % and -10.66 %, respectively. The photocurrent of PbS is strongly dependent on temperature, and enhancement ratio is inversely proportional to the temperature. On the other hand, the graphene/Pbs heterostructures do not exhibit appreciable gating effects. It is argued that the holes and electrons will recombine and the holes transporting to graphene will be reduced much more. From the photocurrent measurements, we observed that the recombination rate of PbS is proportional to temperature and we proposed the photocurrent transmission mechanism of graphene/PbS heterostructure devices. Jian, Wen-Bin 簡紋濱 2014 學位論文 ; thesis 33 zh-TW |
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碩士 === 國立交通大學 === 電子物理系所 === 102 === In this experiment, we probe into photocurrent of graphene devices and graphene/PbS thin film devices. Graphene flakes were made by mechanical exfoliation and PbS thin films were deposited by thermal evaporation.
Due to its feature of a gapless semiconductor, graphene does not exhibit considerable photocurrent effects. The photocurrent of graphene flakes is about 36 nA and the enhancement ratio due to blue light excitation is 1.88 % at 80 K. In contrast, the PbS deposited graphene flakes may show higher photocurrent. It is argued that, after light illumination, the graphene is p-type doped. It implies that only holes transport to graphene after the generation of electron-hole pairs in PbS by light illumination. Therefore, the photocurrent is strongly dependent on the gating field. Though it does not show visible photoresponsivity at 300 K, the photoresponsivity increases largely at 80 K. When the gate biases are applied at -35 V and 35 V, the enhancement ratios raise up to 15.77 % and -10.66 %, respectively.
The photocurrent of PbS is strongly dependent on temperature, and enhancement ratio is inversely proportional to the temperature. On the other hand, the graphene/Pbs heterostructures do not exhibit appreciable gating effects. It is argued that the holes and electrons will recombine and the holes transporting to graphene will be reduced much more. From the photocurrent measurements, we observed that the recombination rate of PbS is proportional to temperature and we proposed the photocurrent transmission mechanism of graphene/PbS heterostructure devices.
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author2 |
Jian, Wen-Bin |
author_facet |
Jian, Wen-Bin Chen, Chau-Bi 陳喬弼 |
author |
Chen, Chau-Bi 陳喬弼 |
spellingShingle |
Chen, Chau-Bi 陳喬弼 Probing photoelectric characteristics of graphene |
author_sort |
Chen, Chau-Bi |
title |
Probing photoelectric characteristics of graphene |
title_short |
Probing photoelectric characteristics of graphene |
title_full |
Probing photoelectric characteristics of graphene |
title_fullStr |
Probing photoelectric characteristics of graphene |
title_full_unstemmed |
Probing photoelectric characteristics of graphene |
title_sort |
probing photoelectric characteristics of graphene |
publishDate |
2014 |
url |
http://ndltd.ncl.edu.tw/handle/15755436008357435322 |
work_keys_str_mv |
AT chenchaubi probingphotoelectriccharacteristicsofgraphene AT chénqiáobì probingphotoelectriccharacteristicsofgraphene AT chenchaubi tàntǎoshímòxīyǔqíbiǎomiànzhēngdùliúhuàqiānbáomó AT chénqiáobì tàntǎoshímòxīyǔqíbiǎomiànzhēngdùliúhuàqiānbáomó |
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