2012 Fiscal Year Final Research Report
Elucidation of efficiency droop mechanism in nitride semiconductorbased light emitting devices by scanning near field optical microscopy
| Project/Area Number |
23686003
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| Research Category |
Grant-in-Aid for Young Scientists (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
Applied materials science/Crystal engineering
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| Research Institution | Kyoto University |
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Principal Investigator |
KANETA Akio 京都大学, 大学院・工学研究科, 助教 (80372572)
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| Project Period (FY) |
2011 – 2012
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| Keywords | 走査プローブ顕微鏡 / 半導体物性 / マルチモード近接場分光 / 過渡レンズ法 / 効率ドループ |
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| Research Abstract |
To clarify main factor of efficiency droop phenomena, we performed PL and time-resolved PL measurement using a scanning near field optical microscope. For the blue sample , although carriers overflow from localization centers under the high carrier density, the capture to nonradiative recombination centers (NRCs) hardly takes place because the potential barriers are formed around the NRCs. On the other hand, for the green sample, the increase of carrier density enhances the diffusion from the strong PL domains to the weak ones corresponding to high In composition area, where a large number of NRCs are distributed in association with threading dislocations. Such carrier recombination dynamics was found to be a major mechanism of the efficiency droop in the green sample due to the increase of both carrier lifetime and number of threading dislocations.
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