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SUMMARY:POB seminar - Pierre Lottigier - "InGaN/GaN quantum wells on Si(11
 1) substrate: Nonradiative recombination channels & Light emission efficie
 ncy improvement"
DTSTART:20230606T181500
DTEND:20230606T191500
DTSTAMP:20260920T053148Z
UID:be1834bde935edd55061a847a54b4a977a15eeae71b7ae753f9fd764
CATEGORIES:Conferences - Seminars
DESCRIPTION:Pierre Lottigier\nEPFL Photonics Chapter (EPC) is pleased to
  invite you to our monthly POB (Pizza-Optics-Beer) seminar! It is set
  to take place on Tuesday\, June 6\, 2023\, at 18:15 in CO 122. This PO
 B seminar will be concluded by the awards ceremony of our photo contest.\n
 \nFor organizational purposes\, please register for the event using this
  doodle before June 6\, 2023.\n\n \n\nThis month\, Pierre Lottigier will 
 give a talk on his work "InGaN/GaN quantum wells on Si(111) substrate: N
 onradiative recombination channels & Light emission efficiency improvement
 " :\n \n\nTo improve our LED lighting technologies\, it is of prime impor
 tance to understand what impacts light-emission efficiency. The formation 
 of threading dislocations during heteroepitaxial growth of semiconductors 
 has historically been considered as a major source of nonradiative recombi
 nation in the active region of III-nitride based optoelectronic devices.\n
  \n\nTo question this\, we investigated the efficiency of typical active 
 layers consisting of single InGaN/GaN quantum wells (QWs) grown on thin (<
  1 μm) GaN buffer layers on silicon (111) substrates exhibiting very high
  threading dislocation densities.\n\nIn this talk\, I will first present i
 ntriguing results from various mesoscopic photoluminescence measurements. 
 Despite the high defect density\, we show that the QW emission efficiency 
 significantly increases upon the insertion of an In-containing underlayer\
 , whose role is to prevent the introduction of point defects during the gr
 owth of InGaN QWs. \n \n\nHence\, we demonstrate that point defects play 
 a key role in limiting the InGaN QW efficiency\, even in samples where the
 ir density (∼ 3 × 109 cm−2) is much lower than that of threading dis
 locations (∼ 2 × 1010 cm−2). To explain the underlying nanoscale mec
 hanisms of our questioning observations\, our journey will take us through
  in-depth investigation of the recombination channels by means of cathodol
 uminescence mappings. \n\n\n\n--\n\nYou don't know POBs?\nPOBs (Pizza-Opti
 cs-Beer) are monthly seminars organized by the student association EPFL Ph
 otonics Chapter.\nA PhD or a postdoc gives a 20-minutes presentation about
  his/her research in photonics. Discussions continue informally around piz
 za and beers!\nThe event is free and open to anyone.\n\nWe thank the Docto
 ral Program in Photonics (EPDO)\, the Society of Photo-Optical Instrumenta
 tion Engineers (SPIE.)\, Optica and SwissPhotonics for their support.
LOCATION:CO 122 https://plan.epfl.ch/?room==CO%20122
STATUS:CONFIRMED
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