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Published byNorman Gaines Modified over 8 years ago
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05/07/18 Optical Characterization of High-Mobility Quantum Well with Low-density Modulation-Doping Toshiyuki Ihara Abstract. I measured PL and PLE spectra of high-mobility 33nm quantum well with low-density modulation doping. The sample 03-11-05.1 contains 2D electron gas (2DEG) of 5.9x10 10 cm -2 without parallel conduction. On the contrary, the sample 03- 24-05.3 contains 2DEG of 3.5x10 10 cm -2 with parallel conduction. The decrease of the 2D electron density due to Indium solder is clearly observed PL scan of 03-24-05.3, where the exciton peak appears at low electron density. The PLE spectra depends on the sample and also on the position (near / far from In solder). We need further investigation to know which is the main origin that causes the spectral differences, the electron density or the parallel conduction.
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Sample information Sample name03-11-05.103-24-05.3 LP Quantum well 330 Å GaAs Barrier10% AlGaAs Si doping3x10 11 cm -2 (7.4A x 11sec) Set back 800 Å 1500 Å Electron density5.9x10 10 cm -2 3.5x10 10 cm -2 Parallel conductionnoyes Indium annealing30s ※ ‘LP’ means ‘Low density’ & ‘Parallel conduction’
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PL scan near Indium solder The decrease of 2D electron density around Indium solder is clearly observed in low-density doped quantum well (03-24-05.3 LP).
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PLE spectra of both samples What causes the difference of PLE spectra, the electron density or parallel conduction?
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PLE spectra measured near / far from In solder Though there are interesting differences, the mechanism is still unclear…
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Measurements of conductivity There are two problems: ① Resistance is large. ② Success rate is low. Further investigation is needed (shorter annealing time, use InSb etc.) …To be continued
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