The dc Electrical Characterization of Hg/delta-GaN/n-GaAs Devices, with Different Thicknesses of the GaN Thin Layers

作者：Zougagh N^*; Benamara Z; Mazari H; Benseddik N; Ameur K; Monier G; Bideux L; Gruzza B

来源：Sensor Letters, 2011, 9(6): 2211-2214.

DOI：10.1166/sl.2011.1817

• Nitridation
• Electrical Characterization
• delta-GaN/n-GaAs
• Annealing
• Heterostructures

This work presents the study of the effect of a thin gallium nitride (GaN) layer, deposited on GaAs substrate. Then, the electrical characterisations are realized using the I-V and C-V measurements. The plotted curves of Hg/delta-GaN/n-GaAs heterostructures, with various thicknesses delta of GaN films, are compared with the Hg/GaAs ones. The thickness of GaN (2.8 nm) deposited on GaAs followed by an annealing operation improves the conduction current. In fact, the (I-V) characteristics reveal a low series. resistance (49 Omega) for the annealed sample compared with a value of 117 Omega obtained in the not annealed ones. Comparing the annealed samples, the significant value of the ideality factor (n > 2.5) is obtained in the nitrided samples with large thickness of the GaN layer. This effect is probably due to the existence of a tunnel current. However, in the sample with a lower thickness (1.8 nm) presents an interessant ideality factor (1.3). The (C-V) characteristics show that the annealing operation decreases the barrier height Phi(bn) (0.69-0.77 eV) for the annealed samples compared with (1.77-1.88 eV) obtained for the not annealed samples. The concentration doping of the samples which have a sufficiently thickness of GaN layer is higher than concentration of GaAs substrate. This effect is probably due to the presence of nitrogen vacancies which are known to act as levels donors in the GaN layer. The value of the interface state density N-ss at mid-gap is about 3 x 10(11) eV(-1) cm(-2) for the nitridated samples showed in Figure 3.

• 出版日期2011-12