Electrical and optical properties of rf triode-sputtered Au films

Abstract

A large number of Au films with different nominal film thicknesses (NFT) from 12 to 960 Å, were rf triode sputtered with 2.5 kV in a single pumpdown in 1-mTorr argon, at a deposition rate of about 1.5 Å/sec, onto amorphous SiO2 at 120 °C. The film substructure, as determined by transmission electron microscopy, showed that the island particles became metallically connected at a NFT of about 30 Å. This small value was attributed to the high nucleation density (about 1.2×1012 nucleated particles/ cm2 at a NFT of 12.7 Å) and to the fact that the island particles grow as flattened platelets. Microscopy also revealed that the islands were composed of small single crystallites with mean dimensions less than 50 Å for a NFT of 20 Å. The surface coverage increased with NFT to about 100% at 100 Å. The mean crystallite increased to about 85 Å and then tended to remain constant for NFT's above 100 Å. The electrical resistivity of films with an NFT greater than 30 Å was measured over the temperature range 77–300 K. In the NFT range 30–40 Å, the films were found to have a very small positive temperature coefficient of resistance (TCR) that increased linearly with NFT from 0.0002 to 0;0004 K−1 and a large sheet resistance that decreased rapidly from 1000 Ω/□ (30 Å) to 100 Ω/□ (40 Å). Films greater than 100 Å had resistivities 3–4 times that reported for single-crystal Au. This increase was mainly attributed to polycrystalline grain boundary scattering. Optical properties were studied by measuring the reflectance and transmission of films over an incident wavelength range from 0.18 to 2.0 μ. Films with NFT's less than 50 Å were found to behave optically according to the Maxwell-Garnett theory for an array of particles, even though the island particles of these films were irregularly shaped. Optical indices were calculated for films thicker than 12 Å.

Heat-Transport and Solar Transmission Through Windows with Low-Emitting Coatings

“…The theoretically predicted data in Figure 4 agreed with measured data down to a film-thickness of 20 nm for Au and 12 nm for Ag [16]. Other investigations have shown that even Au films can be prepared with optical constants resembling those of bulk metals down to a film thickness of 10-12 nm [17]. The ZnS films in the triple layers were assumed non-absorbing and their thicknesses systematically chosen to optimize the solar transmission [18].…”

“…Shown in this figure are also metallic Cu films and ZnS/Cu/ZnS layers which have comparable properties with the other noble-metal based layers. The data for the Cu films necessary to Figure 8 were taken from reference [17] like the data for Au and Ag. The SnO2 which exhibits high absorptance, but a moderate reflectance, is considerably increased in merit compared to the metal-based coatings.…”

Photoinduced Negative Differential Resistivity and Gunn Oscillations in SrTiO3

“…Top semi‐transparent gold electrodes have been deposited on this surface. [ 13 ] The photoconductive properties have been investigated by measuring the current‐voltage (IV) characteristics, respectively the short‐circuit photocurrent at different applied voltages, at different temperatures and under variable photon flux in the range of (10 11 − 10 15 ) cm −2 s −1 for both out‐of‐plane (OOP), i.e., between Au electrodes and bottom silver contact, and in‐plane (IP) geometries. A typical photo‐IV characteristics family under different photon flux is shown in Figure 1 b .…”

“…Top semi-transparent gold electrodes have been deposited on this surface. [13] The photoconductive properties have been investigated by measuring the current-voltage (IV) characteristics, respectively the short-circuit photocurrent at different applied The photocurrent rises very fast with the applied field up to a critical value beyond which the photocurrent quenches rapidly, generating a current peak and an extended negative differential resistivity (NDR) regime. The field and photocurrent peak values are both temperature and photon flux dependent, as can be seen in Figure 1b,c.…”

A Simple Interconnection Layer for Tandem Organic Solar Cells with Improved Efficiency and Fill Factor

“…The thickness of Au was chosen to be 6 nm, as it has been reported that an Au film with thickness less than 5 nm usually leads to a very high resistance and a poor device performance. [12,28] The 𝐽-𝑉 curve of an id-tandem cell with an ICL of Ca (5 nm)/Au (6 nm)/MoO 3 (12 nm) was shown in Fig. 2 (black curve).…”