Dependence of Ni/AlGaN Schottky barrier height on Al mole fraction

Abstract

The dependence of the Schottky barrier height of Ni/Al x Ga 1Ϫx N contact on the Al mole fraction up to xϭ0.23 was studied. The barrier heights were measured by I -V, capacitance-voltage, and the internal photoemission method. The Al mole fractions were estimated from the AlGaN band gap energies measured by photoluminescence. In the range of xϽ0.2 a linear relationship between the barrier height and Al mole fraction was obtained. This was consistent with the slope predicted by the Schottky rule. For xϭ0.23, the measured barrier height was lower than predicted. We believed this was due to crystalline defects at the Ni/AlGaN interface.

Current transport mechanism in graphene/AlGaN/GaN heterostructures with various Al mole fractions

“…In our calculation, the value of m * for Al x Ga 1−x N with Al mole fraction x was calculated by a linear interpolation of the theoretical values for GaN (0.22 m 0 ) and AlN (0.35 m 0 ). 23 According to the Schottky-Mott (SM) theory, the SBH at the interface between graphene and AlGaN is given by φ b = φ G − χ s , where φ G = 4.5 eV is the graphene work function, 24 and χ s is the electron affinity of Al x Ga 1−x N. Since χ s decreases as x increases, the SBH also increases with x. Grabowski et al reported the electron affinities of GaN and AlN as 3.1 eV and 0.25 eV, respectively. 25 On the other hand, some other studies reported that the electron affinities of GaN and AlN are 4.2 eV and 2.05 eV, respectively.…”

“…25 On the other hand, some other studies reported that the electron affinities of GaN and AlN are 4.2 eV and 2.05 eV, respectively. 23,26 Therefore, the calculated SBH value is dependent on the value of Al x Ga 1−x N electron affinity used in the calculation. figure (denoted by a green diamond).…”

Realizing a SnO2-based ultraviolet light-emitting diode via breaking the dipole-forbidden rule

“…43 To further shed light on the origin of the EL emissions, the schematic diagrams of band alignments in the SnO 2 /p-GaN and the SnO 2 /MgO/p-GaN heterojunctions under a forward bias are illustrated in Figures 4e and f, respectively. Considering that the electron affinities of SnO 2 , MgO and GaN are 4.53, 0.80 and 4.20 eV, respectively, [44][45][46] and considering their individual bandgaps, we can deduce a conduction-band offset (CBO) of À0.33 eV and a valenceband offset (VBO) of À0.53 eV at the SnO 2 /p-GaN interface. Similarly, for the SnO 2 /MgO/p-GaN heterojunction, the CBO is À3.73 eV at the SnO 2 /MgO interface, and the VBO is À0.9 eV at the MgO/p-GaN interface.…”

Schottky barrier formation at the Au to rare earth doped GaN thin film interface

“…The European Physical Journal Applied Physics [28] I P E GaN 1.0 [29] I P E GaN 1.11 [24] I P E GaN 0.95 ± 0.04 [26] I P E GaN 0.97 ± 0.05 [27] I P E calculated as 1.33 ± 0.1 eV via (4). The same methods and calculations described above yielded Schottky barrier heights of 1.64 ± 0.1 eV and 1.68 ± 0.1 eV for Er:GaN and Yb:GaN, respectively.…”

“…Surface alloying can occur [14] and a large range of experimentally measured Schottky barrier heights has been reported (0.76-1.40 eV) at the Au to n-type GaN interface [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29], using photoemission spectroscopy (PES), current-voltage (I-V) and capacitance voltage (C-V) characteristics, and internal photoemission [30]. However, the generally accepted value is about 1.08 eV [31].…”