Advanced

Effect of tunable dot charging on photoresponse spectra of GaAs p-i-n diode with InAs quantum dots

Shang, Xiangjun; Yu, Ying; Li, Mifeng; Wang, Lijuan; Zha, Guowei; Ni, Haiqiao; Pettersson, Håkan LU ; Fu, Ying and Niu, Zhichuan (2015) In Applied Physics Reviews 118(24).
Abstract
Quantum dot (QD)-embedded photodiodes have demonstrated great potential for use as detectors. A modulation of QD charging opens intriguing possibilities for adaptive sensing with bias-tunable detector characteristics. Here, we report on a p-i-n GaAs photodiode with InAs QDs whose charging is tunable due to unintentional Be diffusion and trap-assisted tunneling of holes, from bias-and temperature (T)-dependent photocurrent spectroscopy. For the sub-bandgap spectra, the T-dependent relative intensities "QD-s/WL" and "WL/GaAs" (WL: wetting layer) indicate dominant tunneling under -0.9V (trap-assisted tunneling from the top QDs) and dominant thermal escape under -0.2 similar to 0.5V (from the bottom QDs since the top ones are charged and... (More)
Quantum dot (QD)-embedded photodiodes have demonstrated great potential for use as detectors. A modulation of QD charging opens intriguing possibilities for adaptive sensing with bias-tunable detector characteristics. Here, we report on a p-i-n GaAs photodiode with InAs QDs whose charging is tunable due to unintentional Be diffusion and trap-assisted tunneling of holes, from bias-and temperature (T)-dependent photocurrent spectroscopy. For the sub-bandgap spectra, the T-dependent relative intensities "QD-s/WL" and "WL/GaAs" (WL: wetting layer) indicate dominant tunneling under -0.9V (trap-assisted tunneling from the top QDs) and dominant thermal escape under -0.2 similar to 0.5V (from the bottom QDs since the top ones are charged and inactive for optical absorption) from the QD s-state, dominant tunneling from WL, and enhanced QD charging at >190K (related to trap level ionization). For the above-bandgap spectra, the degradation of the spectral profile (especially near the GaAs bandedge) as the bias and T tune (especially under -0.2 similar to 0.2V and at >190 K) can be explained well by the enhanced photoelectron capture in QDs with tunable charging. The dominant spectral profile with no degradation under 0.5V is due to a saturated electron capture in charged QDs (i.e., charging neutralization). QD level simulation and schematic bandstructures can help one understand these effects. (C) 2015 AIP Publishing LLC. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Applied Physics Reviews
volume
118
issue
24
publisher
American Institute of Physics
external identifiers
  • wos:000367535100026
  • scopus:84953857669
ISSN
0021-8979
DOI
10.1063/1.4937408
language
English
LU publication?
yes
id
2b7745d8-3577-4c73-8a55-07eab384a727 (old id 8761412)
date added to LUP
2016-02-22 14:33:50
date last changed
2017-01-01 04:11:20
@article{2b7745d8-3577-4c73-8a55-07eab384a727,
  abstract     = {Quantum dot (QD)-embedded photodiodes have demonstrated great potential for use as detectors. A modulation of QD charging opens intriguing possibilities for adaptive sensing with bias-tunable detector characteristics. Here, we report on a p-i-n GaAs photodiode with InAs QDs whose charging is tunable due to unintentional Be diffusion and trap-assisted tunneling of holes, from bias-and temperature (T)-dependent photocurrent spectroscopy. For the sub-bandgap spectra, the T-dependent relative intensities "QD-s/WL" and "WL/GaAs" (WL: wetting layer) indicate dominant tunneling under -0.9V (trap-assisted tunneling from the top QDs) and dominant thermal escape under -0.2 similar to 0.5V (from the bottom QDs since the top ones are charged and inactive for optical absorption) from the QD s-state, dominant tunneling from WL, and enhanced QD charging at >190K (related to trap level ionization). For the above-bandgap spectra, the degradation of the spectral profile (especially near the GaAs bandedge) as the bias and T tune (especially under -0.2 similar to 0.2V and at >190 K) can be explained well by the enhanced photoelectron capture in QDs with tunable charging. The dominant spectral profile with no degradation under 0.5V is due to a saturated electron capture in charged QDs (i.e., charging neutralization). QD level simulation and schematic bandstructures can help one understand these effects. (C) 2015 AIP Publishing LLC.},
  articleno    = {244503},
  author       = {Shang, Xiangjun and Yu, Ying and Li, Mifeng and Wang, Lijuan and Zha, Guowei and Ni, Haiqiao and Pettersson, Håkan and Fu, Ying and Niu, Zhichuan},
  issn         = {0021-8979},
  language     = {eng},
  number       = {24},
  publisher    = {American Institute of Physics},
  series       = {Applied Physics Reviews},
  title        = {Effect of tunable dot charging on photoresponse spectra of GaAs p-i-n diode with InAs quantum dots},
  url          = {http://dx.doi.org/10.1063/1.4937408},
  volume       = {118},
  year         = {2015},
}