title: Impurity Resonant States p-type Doping in Wide-Band-Gap Nitrides.
abstract: In this work, a new strategy for achieving efficient p-type doping in high bandgap nitride semiconductors to overcome the fundamental issue of high activation energy has been proposed and investigated theoretically, and demonstrated experimentally. Specifically, in an AlxGa(1-x)N/GaN superlattice structure, by modulation doping of Mg in the AlxGa(1-x)N barriers, high concentration of holes are generated throughout the material. A hole concentration as high as 1.1 × 10(18) cm(-3) has been achieved, which is about one order of magnitude higher than that typically achievable by direct doping GaN. Results from first-principle calculations indicate that the coupling and hybridization between Mg 2p impurity and the host N 2p orbitals are main reasons for the generation of resonant states in the GaN wells, which further results in the high hole concentration. We expect this approach to be equally applicable for other high bandgap materials where efficient p-type doing is difficult. Furthermore, a two-carrier-species Hall-effect model is proposed to delineate and discriminate the characteristics of the bulk and 2D hole, which usually coexist in superlattice-like doping systems. The model reported here can also be used to explain the abnormal freeze-in effect observed in many previous reports.
authors.affiliation: Research and Development Center for Solid State Lighting, Institute of Semiconductors, Chinese Academy of Science, Beijing, 100086, China.|State Key Laboratory of Solid State Lighting, Beijing, 100086, China.
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Liu
authors.affiliation: Research and Development Center for Solid State Lighting, Institute of Semiconductors, Chinese Academy of Science, Beijing, 100086, China.|State Key Laboratory of Solid State Lighting, Beijing, 100086, China.
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Yi
authors.affiliation: Research and Development Center for Solid State Lighting, Institute of Semiconductors, Chinese Academy of Science, Beijing, 100086, China.|State Key Laboratory of Solid State Lighting, Beijing, 100086, China.
authors.forename: Zhiguo
authors.initials: Z
authors.lastname: Yu
authors.affiliation: Research and Development Center for Solid State Lighting, Institute of Semiconductors, Chinese Academy of Science, Beijing, 100086, China.|State Key Laboratory of Solid State Lighting, Beijing, 100086, China.
authors.forename: Guodong
authors.initials: G
authors.lastname: Yuan
authors.affiliation: School of Physics and Engineering, Sun Yat-Sen University, Guangzhou 510275, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Research and Development Center for Solid State Lighting, Institute of Semiconductors, Chinese Academy of Science, Beijing, 100086, China.|State Key Laboratory of Solid State Lighting, Beijing, 100086, China.
authors.forename: Junxi
authors.initials: J
authors.lastname: Wang
authors.affiliation: Research and Development Center for Solid State Lighting, Institute of Semiconductors, Chinese Academy of Science, Beijing, 100086, China.|State Key Laboratory of Solid State Lighting, Beijing, 100086, China.
authors.forename: Jinmin
authors.initials: J
authors.lastname: Li
authors.affiliation: Lyles School of Civil Engineering, Purdue University, West Lafayette, IN 47907, USA.
authors.forename: Na
authors.initials: N
authors.lastname: Lu
authors.affiliation: College of Engineering and Computing, Missouri University of Science and Technology, 305 McNutt Hall, 1400 N. Bishop, Rolla, MO 65409, USA.
authors.forename: Ian
authors.initials: I
authors.lastname: Ferguson
authors.affiliation: Department of Electrical and Computer Engineering, The University of North Carolina at Charlotte, 9201 University City Blvd., Charlotte, North Carolina 28223, USA.
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhang