PMID- 36586983
OWN - NLM
STAT- PubMed-not-MEDLINE
DCOM- 20230102
LR  - 20230103
IS  - 1089-7690 (Electronic)
IS  - 0021-9606 (Linking)
VI  - 157
IP  - 24
DP  - 2022 Dec 28
TI  - Impact of random alloy fluctuations on the electronic and optical properties of 
      (Al,Ga)N quantum wells: Insights from tight-binding calculations.
PG  - 244705
LID - 10.1063/5.0132490 [doi]
AB  - Light emitters based on the semiconductor alloy aluminum gallium nitride 
      [(Al,Ga)N] have gained significant attention in recent years due to their 
      potential for a wide range of applications in the ultraviolet (UV) spectral 
      window. However, current state-of-the-art (Al,Ga)N light emitters exhibit very 
      low internal quantum efficiencies (IQEs). Therefore, understanding the 
      fundamental electronic and optical properties of (Al,Ga)N-based quantum wells is 
      key to improving the IQE. Here, we target the electronic and optical properties 
      of c-plane Al(x)Ga(1-x)N/AlN quantum wells by means of an empirical atomistic 
      tight-binding model. Special attention is paid to the impact of random alloy 
      fluctuations on the results as well as the Al content x in the well. We find that 
      across the studied Al content range (from 10% to 75% Al), strong hole wave 
      function localization effects are observed. Additionally, with increasing Al 
      content, electron wave functions may also start to exhibit carrier localization 
      features. Overall, our investigations on the electronic structure of c-plane 
      Al(x)Ga(1-x)N/AlN quantum wells reveal that already random alloy fluctuations are 
      sufficient to lead to (strong) carrier localization effects. Furthermore, our 
      results indicate that random alloy fluctuations impact the degree of optical 
      polarization in c-plane Al(x)Ga(1-x)N quantum wells. We find that the switching 
      from transverse electric to transverse magnetic light polarization occurs at 
      higher Al contents in the atomistic calculation, which accounts for random alloy 
      fluctuations, compared to the widely used virtual crystal approximation approach. 
      This observation is important for light extraction efficiencies in (Al,Ga)N-based 
      light emitting diodes operating in the deep UV.
FAU - Finn, Robert
AU  - Finn R
AUID- ORCID: 0000-0003-4459-8780
AD  - Tyndall National Institute, University College Cork, Cork T12 R5CP, Ireland.
FAU - Schulz, Stefan
AU  - Schulz S
AUID- ORCID: 0000-0002-8178-8383
AD  - Tyndall National Institute, University College Cork, Cork T12 R5CP, Ireland.
LA  - eng
PT  - Journal Article
PL  - United States
TA  - J Chem Phys
JT  - The Journal of chemical physics
JID - 0375360
SB  - IM
EDAT- 2023/01/01 06:00
MHDA- 2023/01/01 06:01
CRDT- 2022/12/31 22:03
PHST- 2022/12/31 22:03 [entrez]
PHST- 2023/01/01 06:00 [pubmed]
PHST- 2023/01/01 06:01 [medline]
AID - 10.1063/5.0132490 [doi]
PST - ppublish
SO  - J Chem Phys. 2022 Dec 28;157(24):244705. doi: 10.1063/5.0132490.