On the profile of frequency dependent dielectric properties of (Ni/Au)/GaN/Al0.3Ga0.7N heterostructures

Abstract

a b s t r a c tThe voltage (V) and frequency (f) dependence of dielectric characteristics such as dielectric constant (e 0 ), dielectric loss (e 00 ), dielectric loss tangent (tan d) and real and imaginary part of electrical modulus (V 0 and M 00 ) of the (Ni/Au)/GaN/Al 0.3 Ga 0.7 N heterostructures have been investigated by using experimental admittance spectroscopy (capacitance-voltage (C-V) and conductance-voltage (G/w-V)) measurements at room temperature. Experimental results show that the values of the e 0 , e 00 , tan d and the real and imaginary parts of the electric modulus (V 0 and M 00 ) obtained from the C and G/w measurements were found to be strong function of frequency and applied bias voltage especially in depletion region at low frequencies. These changes in dielectric parameters can be attributed to the interfacial GaN cap layer, interface polarization and a continuous density distribution of interface states and their relaxation time at metal/semiconductor interface. While the values of the e 0 decrease with increasing frequencies, tan d, V 0 and M 00 increase with the increasing frequency. Also, the dielectric loss (e 00 ) have a local maximum at about frequency of 100 kHz. It can be concluded that the interface polarization can occur more easily at low frequencies with the number of interface states located at the metal/semiconductor interface.

Influence of interfacial layer thickness on frequency dependent dielectric properties and electrical conductivity in Al/Bi4Ti3O12/p-Si structures

“…10,15,19,[23][24][25][26][27]30,31 Another important dielectric parameter is loss tangent (tan d) that shows to which extent the material is lossy, and it is given by the ratio of e 00 to e 0 as following: 10,19,20,[23][24][25]27,30,31 10,15,19,[23][24][25][26][27]30,31 Another important dielectric parameter is loss tangent (tan d) that shows to which extent the material is lossy, and it is given by the ratio of e 00 to e 0 as following: 10,19,20,[23][24][25]27,30,31 …”

“…1. 15,19,20,[23][24][25][26] Thus, it can be assumed that higher e 0 values for MFS structure with thicker layer indicate that higher density of interface states (D it ) exists for MFS-53 nm. The dispersion in e 0 in terms of layer thickness is more obvious at lower frequencies; however, it tends to lose strength toward high frequency region; suggesting e 0 becomes almost independent of layer thickness at high frequencies.…”

“…The underlying reason that this formalism has been used by many researchers 15,[19][20][21][22][23][24][25][26] is that better understanding of bulk dielectric response is realized. The underlying reason that this formalism has been used by many researchers 15,[19][20][21][22][23][24][25][26] is that better understanding of bulk dielectric response is realized.…”

Enhancement of Dielectric Characteristics of Polyvinyl Alcohol (PVA) Interfacial Layer in Au/PVA/n‐Si Structures by Bi2O3Disperse

“…The values of e′ and e″, in the case of admittance measurements, can be expressed and follows [25][26][27][28][29][30] The values of e′ and e″, in the case of admittance measurements, can be expressed and follows [25][26][27][28][29][30] …”

“…Figure 2 shows the values of e′, e″, and tand of Au/PVA (Bi 2 O 3 -dispersed)/n-Si MPS structure as a function of voltage at various frequencies. 27,30,31 The increasing in e′ values, describing the stored energy, can be attributed to the presence of a possible interface polarization mechanism, because localized charge dipole and interface states can follow the ac signal at low frequencies and contribute to both the capacitance and the dielectric constant values. As can be seen in Fig.…”