BEGIN:VCALENDAR VERSION:2.0 CALSCALE:GREGORIAN PRODID:UW-Madison-Physics-Events BEGIN:VEVENT SEQUENCE:0 UID:UW-Physics-Event-7970 DTSTART:20221018T130000Z DURATION:PT1H0M0S DTSTAMP:20260414T153818Z LAST-MODIFIED:20221013T223104Z LOCATION:EH 4610 in Engineering Hall SUMMARY:Characterizations of ultrathin interfacial atomic-layer-deposi ted oxides and nitrides for semiconductor grafting applications\, Thes is Defense\, Jiarui Gong\, Physics Graduate Student DESCRIPTION:Lattice-mismatched heterogeneous semiconductor grafting te chnique has been developed recently to combine lattice-mismatched semi conductors and create innovative devices. An ultrathin oxide (UO) depo sited by atomic layer deposition (ALD) at the grafted interface has be en recognized as a passivation and tunneling layer\, which plays an im portant role in improving the junction performance\, such as achieving higher on/off ratio and lower ideality factor in a pn junction. To be tter understand the influence of the ALD UO\, various experiments have been conducted to characterize some electrical properties of the ALD UO in various semiconductor systems. In the first part of the presenta tion\, the history of semiconductor heterostructures and the developme nt of semiconductor grafting technique are reviewed. In the second par t\, the interfaces between the UO and several semiconductors were char acterized by X-ray photoelectron spectroscopy (XPS). Various electron states were observed through peak fitting. The correlation between the passivation effect and the electron states was established. In the th ird part\, the surface band-bending of c-plane Ga-face GaN with variou s UO/UN layers was characterized by XPS measurements. The valence band offset (VBO) between GaN and the UO/UN was calculated from the GaN va lence band spectra. The possibility of fabricating an AlGaAs/GaAs/GaN npn heterojunction bipolar transistor (HBT) was examined through simul ation. In the last part\, a novel releasing and transfer printing meth od of the single-crystalline AlN nanomembrane (NM) was introduced. The properties of the AlN were characterized both before and after the wh ole process and no degradation was observed. The possibility of obtain ing high-quality single-crystalline AlN NM brings new potentials to th e semiconductor grafting technique. URL:https://www.physics.wisc.edu/events/?id=7970 END:VEVENT END:VCALENDAR