Simultaneously achieving higher carriers concentration and mobility is a technical challenge against up-scaling the transparent-conductive performances of transparent-conductive oxides. Utilizing one order higher dense (∼1 × 10¹¹ cm⁻³) plasmas (in comparison to the conventional direct current plasmas), highly c-axis oriented Al-doped ZnO films have been prepared with precise control over relative composition and chemical states of constituting elements. Tailoring of intrinsic (O vacancies) and extrinsic (ionic Al and zero-valent Al) dopants provide simultaneous enhancement in mobility and concentration of charge carriers. Room-temperature resistivity as low as 4.89 × 10⁻⁴ Ω cm along the carrier concentration 5.6 × 10²⁰ cm⁻³ is obtained in 200 nm thick transparent films. Here, the control of atomic Al reduces the charge trapping at grain boundaries and subdues the effects of grain boundary scattering. A mechanism based on the correlation between electron-hole interaction and carrier mobility is proposed for degenerately doped wide band-gap semiconductors.

This work reports investigation of the Al-doped ZnO (AZO) film deposition process, at different working pressures, in a conventional magnetron sputtering system. The primary goal of this study is to investigate the plasma formation and deposition process using various diagnostic tools, by utilizing low-temperature deposition process. In addition, this paper also presents a systematic Langmuir probe (LP) analysis procedure to determine the maximum information about plasma parameters. For the present study, we have extensively used LP method to characterize the deposition process for the control of plasma parameters. Along with the LP method, we have also used optical emission spectroscopy diagnostic to examine the favorable deposition condition for the fabrication of conductive AZO film. Utilizing diagnostics, this also reports measurements of ion current density, substrate temperature, and deposition rates to fabricate low resistivity films of ∼3 mΩ cm.

Atmospheric pressure plasma (APP) jets or plasma plumes have recently shown the potential for applications such as plasma surface modification and plasma medicine. These applications need insight into their plasma chemistry and discharge behavior, which are strongly influenced by the plasma parameters. In contrast to conventional APP jet devices, the present study utilizes a combination of six electrodes, and the outer ground electrodes are separated by Teflon to form a moderate-sized plasma column of nearly 10 mm. This atmospheric pressure plasma jet can be used to generate non-thermal plasma bullets away from the plasma generation region. The characteristics of the plasma plume were extensively diagnosed using current–voltage measurements, ICCD camera, and optical emission spectroscopy (OES). The APP plasmas, excited by a relatively low-pulsed dc voltage, were characterized in terms of discharge power, gas temperature, electron excitation temperature, electron temperature, and electron density. With simplified assumptions, these discharge parameters were determined from the OES measurements. Electron densities of the orders of magnitude of 10¹⁴ and 10¹⁵ cm⁻³ relevant to the electron temperature from ∼1.5 to 1.8 eV were obtained for the center regions in the jet discharge when the discharge power was varied from ∼10 to 55 W. Moreover, the effect of various operating parameters on the APP jet propagation was studied, and it was observed that the applied voltage plays a crucial role in the propagation of the plasma jet. Additionally, experiments involving APP plasma treatment on deionized water demonstrate noticeable effects of the He gas flow rate on the discharge behavior near the liquid surface. With the increase in the gas flow rate, the plasma column diameter on the liquid surface increases. Further, the deionized water treated with the APP jet shows the signatures of various active species such as oxygen and nitrogen, which are attributed to the transfer of the charged particles to the liquid. Moreover, due to a relatively low gas temperature (∼310–330 K) along with a high plasma plume, the possibility for the plasma application of this device was realized.

This paper reports the synthesis of flexible indium tin oxide (ITO) films in a dual pulse magnetron sputtering (DPMS) system at low temperature (<100 °C) deposition condition. This study also presents experimental demonstration of the ITO films for their possible use in the fabrication of organic light emitting diode (OLED) device, and the device performance on the super polycarbonate substrates. The presented data reveals the feasibility of ITO films, with a very low sheet resistance of ∼30 Ω/□ and high transmittance of ∼88% at 550 nm, simply by the magnetron pulse mode operations with increasing pulse frequency from 0 to 50 kHz.