Analysis of Electrical Characteristics of Pd/n-Nanocarbon/p-Si Heterojunction Diodes: By C-V-f and G/w-V-f

Abstract

Diamond films are candidate for a wide range of applications, due to their wide band gap, high thermal conductivity, and chemical stability. In this report, diamond-based heterojunction diodes (HJDs) were fabricated by growing n-type nanocarbon composite in the form of nitrogen-doped ultrananocrystalline diamond/amorphous carbon (UNCD/a-C:H:N) films onto p-type Si substrates. X-ray photoemission and the Fourier transform infrared spectroscopies were employed to examine the contribution of nitrogen atoms from the gas phase into the deposited films. The results indicate the incorporation of nitrogen atoms into the grain boundaries of UNCD/a-C:H film by replacing hydrogen atoms. The capacitance- (C-V-f), conductance- (G/ω-V-f), and series resistance-voltage characteristics of the fabricated Pd/n-(UNCD/a-C:H:N)/p-Si HJDs were studied in the frequency range of 40 kHz-2 MHz. The existence of interface states (Nss) and series resistance (Rs) were attributed to the interruption of the periodic lattice structure at the surface of the fabricated junction as well as the defects on the (UNCD/a-C:H:N)/Si interface. By increasing the frequency (≥500 kHz), the Nss reveals an almost frequency-independent behavior, which indicates that the charges at the interface states cannot follow ac signal at higher frequency. The obtained results demonstrated that the UNCD/a-C:H:N is a promising n-type semiconductor for diamond-based heterostructure diodes.

Determination of trap density-of-states distribution of nitrogen-doped ultrananocrystalline diamond/hydrogenated amorphous carbon composite films

“…A coaxial arc plasma gun (CAPG) equipped with pure graphite targets was fixed inside the deposition chamber. A capacitor of 720 μF and 100 V power supply was used to operate the CAPG [21][22][23][24][25][26][27][28][29][30][31][32] . The chamber was initially evacuated to a pressure less than 10 -5 Pa, using a turbo molecular pump.…”

“…Nitrogen atoms incorporate into the GBs rather than the UNCD grains, which results in the creation of localized electronic states within the N 2 -doped UNCD/a-C:H bandgap (1.28 eV). Electron spin resonance (ESR) measurement of UNCD/a-C films exhibited a dangling bond density of 10 22 cm -3 [21] . These dangling bonds might formulate localized electronic states in the UNCD bandgap.…”

Laser-Induced Phosphorus-Doped Conductive Layer Formation on Single-Crystal Diamond Surfaces

“…12,13 In addition, diamond films with higher nitrogen contents exhibit a high amount of sp 2 phases. 14,15 Consequently, phosphorus would be a more plausible typical n-type dopant for diamond if successful incorporation is achieved. 5,16 Techniques such as ion implantations were also presented for post doping of diamond; however, it damaged the diamond, and high-temperature annealing after that led to graphitization.…”

“…Due to insufficient dopant solubility, deep energy levels of impurities, and the ability of the host crystal to spontaneously create intrinsic defects that compensate the dopant species, the n-type doping of diamond is still limited . Nitrogen is the most substitutional candidate donor due to its small covalent radii and high solubility. , However, it forms a deep donor level in the diamond band gap; thus, it does not provide a sufficient number of electrons for conduction at room temperature. , In addition, diamond films with higher nitrogen contents exhibit a high amount of sp 2 phases. , Consequently, phosphorus would be a more plausible typical n-type dopant for diamond if successful incorporation is achieved. , …”

Modeling, design, and simulation of Schottky diodes based on ultrananocrystalline diamond composite films

“…One form of UNCD material is known as the ultrananocrystalline diamond/amorphous hydrogenated carbon (UNCD/a-C:H) composite. In this material, nanoscale diamond grains are extremely spread in a hydrogenated amorphous carbon (a-C:H) matrix that is grown in a controlled hydrogen ambient [21][22][23][24][25][26][27][28]. The GBs in UNCD/a-C:H mainly contain a large amount of disordered mixture of sp 2 /sp 3 -bonded carbon, while the UNCD grains mainly incorporate pure sp 3 -bonding [3].…”