1. The School of Physics and Electronics, Hunan University, Changsha, China
2. College of Semiconductors (College of Integrated Circuits), Hunan University, Changsha, China
3. Departament d’Enginyeria Electrònica, Elèctrica i Automàtica, Universitat Rovira i Virgili, Tarragona, Spain
4. Institute of Information and Communication Technologies, Electronics and Applied Mathematics (ICTEAM), Université Catholique de Louvain, Leuven-la-Neuve, Belgium