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Jin EN, Hardy MT, Mock AL, Lyons JL, Kramer AR, Tadjer MJ, Nepal N, Katzer DS, Meyer DJ. Band Alignment of Sc xAl 1-xN/GaN Heterojunctions. ACS APPLIED MATERIALS & INTERFACES 2020; 12:52192-52200. [PMID: 33146516 DOI: 10.1021/acsami.0c15912] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
ScAlN is an emergent ultrawide-band-gap material with both a high piezoresponse and demonstrated ferroelectric polarization switching. Recent demonstration of epitaxial growth of ScAlN on GaN has unlocked prospects for new high-power transistors and nonvolatile memory technologies fabricated from these materials. An understanding of the band alignments between ScAlN and GaN is crucial in order to control the electronic and optical properties of engineered devices. To date, there have been no experimental studies of the band offsets between ScAlN and GaN. This work presents optical characterization of the band gap of molecular beam epitaxy grown ScxAl1-xN using spectroscopic ellipsometry and measurements of the band offsets of ScxAl1-xN with GaN using X-ray photoemission spectroscopy, along with a comparison to first-principles calculations. The band gap is shown to continuously decrease as a function of increasing ScN alloy fraction with a negative bowing parameter. Furthermore, a crossover from straddling (type-I) to staggered (type-II) band offsets is demonstrated as Sc composition increases beyond approximately x = 0.11. These results show that the ScAlN/GaN valence band alignment can be tuned by changing the Sc alloy fraction, which can help guide the design of heterostructures in future ScAlN/GaN-based devices.
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Affiliation(s)
- Eric N Jin
- NRC Research Associateship Programs, 500 Fifth Street, Washington, DC 20001, United States
| | - Matthew T Hardy
- Electronics Science and Technology Division, U.S. Naval Research Laboratory, 4555 Overlook Avenue, Southwest, Washington, DC 20375, United States
| | - Alyssa L Mock
- NRC Research Associateship Programs, 500 Fifth Street, Washington, DC 20001, United States
| | - John L Lyons
- Center for Computational Materials Science, U.S. Naval Research Laboratory, 4555 Overlook Avenue, Southwest, Washington, DC 20375, United States
| | - Alan R Kramer
- NRC Research Associateship Programs, 500 Fifth Street, Washington, DC 20001, United States
| | - Marko J Tadjer
- Electronics Science and Technology Division, U.S. Naval Research Laboratory, 4555 Overlook Avenue, Southwest, Washington, DC 20375, United States
| | - Neeraj Nepal
- Electronics Science and Technology Division, U.S. Naval Research Laboratory, 4555 Overlook Avenue, Southwest, Washington, DC 20375, United States
| | - D Scott Katzer
- Electronics Science and Technology Division, U.S. Naval Research Laboratory, 4555 Overlook Avenue, Southwest, Washington, DC 20375, United States
| | - David J Meyer
- Electronics Science and Technology Division, U.S. Naval Research Laboratory, 4555 Overlook Avenue, Southwest, Washington, DC 20375, United States
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Zheng M, Lin S, Xu L, Zhu L, Wang ZL. Scanning Probing of the Tribovoltaic Effect at the Sliding Interface of Two Semiconductors. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e2000928. [PMID: 32270901 DOI: 10.1002/adma.202000928] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 03/16/2020] [Accepted: 03/17/2020] [Indexed: 06/11/2023]
Abstract
Contact electrification (CE or triboelectrification) is a common phenomenon, which can occur for almost all types of materials. In previous studies, the CE between insulators and metals has been widely discussed, while CE involving semiconductors is only recently. Here, a tribo-current is generated by sliding an N-type diamond coated tip on a P-type or N-type Si wafers. The density of surface states of the Si wafer is changed by introducing different densities of doping. It is found that the tribo-current between two sliding semiconductors increases with increasing density of surface states of the semiconductor and the sliding load. The results suggest that the tribo-current is induced by the tribovoltaic effect, in which the electron-hole pairs at the sliding interface are excited by the energy release during friction, which may be due to the transition of electrons between the surface states during contact, or bond formation across the sliding interface. The electron-hole pairs at the sliding interface are subsequently separated by the built-in electric field at the PN or NN heterojunctions, which results in a tribo-current, in analogy to that which occurs in the photovoltaic effect.
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Affiliation(s)
- Mingli Zheng
- Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, Beijing, 100083, P. R. China
- School of Nanoscience and Technology, University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Shiquan Lin
- Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, Beijing, 100083, P. R. China
- School of Nanoscience and Technology, University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Liang Xu
- Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, Beijing, 100083, P. R. China
- School of Nanoscience and Technology, University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Laipan Zhu
- Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, Beijing, 100083, P. R. China
- School of Nanoscience and Technology, University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Zhong Lin Wang
- Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, Beijing, 100083, P. R. China
- School of Nanoscience and Technology, University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA, 30332-0245, USA
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Ni WX, Hansson GV. Band offsets in pseudomorphically grown Si/Si1-xGex heterostructures studied with core-level x-ray photoelectron spectroscopy. PHYSICAL REVIEW. B, CONDENSED MATTER 1990; 42:3030-3037. [PMID: 9995796 DOI: 10.1103/physrevb.42.3030] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Pearsall TP, Bevk J, Bean JC, Bonar J, Mannaerts JP, Ourmazd A. Electronic structure of Ge/Si monolayer strained-layer superlattices. PHYSICAL REVIEW. B, CONDENSED MATTER 1989; 39:3741-3757. [PMID: 9948696 DOI: 10.1103/physrevb.39.3741] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Schwartz GP, Hybertsen MS, Bevk J, Nuzzo RG, Mannaerts JP, Gualtieri GJ. Core-level photoemission measurements of valence-band offsets in highly strained heterojunctions: Si-Ge system. PHYSICAL REVIEW. B, CONDENSED MATTER 1989; 39:1235-1241. [PMID: 9948308 DOI: 10.1103/physrevb.39.1235] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Menéndez J. Tetrahedral semiconductors: Constancy of the midgap energies with respect to the vacuum level. PHYSICAL REVIEW. B, CONDENSED MATTER 1988; 38:6305-6307. [PMID: 9947097 DOI: 10.1103/physrevb.38.6305] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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