High-density polarization-induced 2D electron gases in N-polar pseudomorphic undoped GaN/Al0.85Ga0.15N heterostructures on single-crystal AlN substrates
Abstract
The polarization difference and band offset between Al(Ga)N and GaN induce two-dimensional (2D) free carriers in Al(Ga)N/GaN heterojunctions without any chemical doping. A high-density 2D electron gas (2DEG), analogous to the recently discovered 2D hole gas in a metal-polar structure, is predicted in a N-polar pseudomorphic GaN/Al(Ga)N heterostructure on unstrained AlN. We report the observation of such 2DEGs in N-polar undoped pseudomorphic GaN/AlGaN heterostructures on single-crystal AlN substrates by molecular beam epitaxy. With a high electron density of ∼4.3 ×1013/cm2 that maintains down to cryogenic temperatures and a room temperature electron mobility of ∼450 cm2/V s, a sheet resistance as low as ∼320 Ω/◻ is achieved in a structure with an 8 nm GaN layer. These results indicate significant potential of AlN platform for future high-power RF electronics based on N-polar III-nitride high electron mobility transistors.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Aug 22, 2022
- Source ID
- 10.1063/5.0107159
Entities
People
- Debdeep Jena
- Eungkyun Kim
- Huili Grace Xing
- Jashan Singhal
- Jimy Encomendero Risco
- Kazuki Nomoto
- Masato Toita
- Yong-Jin Cho
- Zexuan Zhang
Organizations
- Air Force Office of Scientific Research
- Asahi Kasei
- Cornell University
- National Science Foundation
- United States Department of Energy