The temperature dependence of carrier transport properties of AlxGa 1−x N/InyGa 1−y N/GaN and AlxGa 1−x N/GaN heterostructures has been investigated.It is shown that the Hall mobility in Al 0.25 Ga 0.75 N/In 0.03 Ga 0.97 N/GaN heterostructures is higher than that in Al 0.25 Ga 0.75 N/GaN heterostructures at temperatures above 500 K, even the mobility in the former is much lower than that in the latter at 300 K. More importantly, the electron sheet density in Al 0.25 Ga 0.75 N/In 0.03 Ga 0.97 N/GaN heterostructures decreases slightly, whereas the electron sheet density in Al 0.25 Ga 0.75 N/GaN heterostructures gradually increases with increasing temperature above 500 K. It is believed that an electron depletion layer is formed due to the negative polarization charges at the InyGa 1−y N/GaN heterointerface induced by the compressive strain in the InyGa 1−y N channel, which effectively suppresses the parallel conductivity originating from the thermal excitation in the underlying GaN layer at high temperatures.
Huang Cheng-Cheng(黄 呈橙) a) , Zhang Xia(张 霞) a) , Xu Fu-Jun(许福军) a) † , Xu Zheng-Yu(许正昱) a) , Chen Guang(陈 广) a) , Yang Zhi-Jian(杨志坚) a) , Tang Ning(唐 宁) a) , Wang Xin-Qiang(王新强) a)b) , and Shen Bo(沈 波) a)b) ‡ a) State
The surface state properties (such as surface state density, time constant and level position related to the bottom of InAlN conduction band) of Ni/Au/-InAlN Schottky barrier diodes with nearly lattice matched (InN=18%) and tensilely (15%) or compressively (21%) strained InAlN barrier layer were evaluated, by using current-voltage (I-V), frequency-dependent capacitance-voltage (C-V) measurements and atomic force microscope (AFM) images. It was found that, with increasing content of In the surface state density increased and the barrier height of the Schottky contacts decreased, respectively. The C-V curves shifted toward the positive bias values with reducing measured frequencies, which became more apparent with increasing In content. It may be due to the hole emission from the surface states of Ni/Au/-InAlN Schottcky contacts. Atomic force microscope (AFM) images indicated that the InAlN surface became rougher with increasing In content, which may be the main reason for the increased surface state densities.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.