Tunable‐Conduction‐Band In–Zn–O‐Based Transparent Conductive Oxide Deposited at Room Temperature. Issue 13 (27th May 2022)

• Record Type: Journal Article
• Authors: Ishida, Taichi; Nishimura, Takahito; Chantana, Jakapan; Mavlonov, Abdurashid; Kawano, Yu; Negami, Takayuki; Minemoto, Takashi
• Is Part Of: Physica status solidi. Volume 219:Issue 13(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-05-27
• Subjects: AZO -- conduction band -- IZO -- MgO -- mobility -- room-temperature deposition -- solar cells; Solid state physics -- Periodicals; Solids -- Industrial applications -- Periodicals; 530.41
• DOI: 10.1002/pssa.202200061
• Languages: English
• ISSNs: 1862-6300

Abstract

Abstract : Aluminum (Al)‐doped indium zinc magnesium oxide (Al:IZMO)‐based transparent conductive oxide (TCO) films with a tunable conduction band structure are developed via deposition at room temperature under radio‐frequency (RF) magnetron co‐sputtering for the application of highly efficient photovoltaic devices. First, at the amorphous phase region with the [In]/([In] + [Zn]) compositional ratio of 0.5–0.8, Al‐doped indium zinc oxide (Al:IZO) films obtained by introducing a small amount of aluminum oxide (Al2 O3 ) exhibit higher Hall mobility and lower carrier density than those of indium zinc oxide (IZO) without Al doping. Second, adding magnesium oxide (MgO) to Al:IZO allows the optical bandgap ( E g ) control, with constant ionization energy of −7.31 eV, which can be expressed by E g = 0.83 y + 3.33 (eV) as a function of [Mg]/([Zn] + [Mg]) compositional ratio ( y ) (in the y value region of 0–0.12). This result suggests that the conduction band minimum can be tuned by 0.067 eV under the 8% Mg substitution into the Zn site in the Al:IZMO films while remaining valence band maximum. Al:IZMO‐based TCO films with conduction band controllability are deposited at room temperature for preventing thermal damage. These findings contribute to the device design and development of emerging photovoltaic applications. Abstract : Aluminum‐doped indium zinc magnesium oxide (Al:IZMO)‐based transparent conductive oxide films are developed via co‐sputtering deposition at room temperature. A conduction band minimum can be tuned by 0.067 eV under the 8% Mg substitution into the Zn site. The Al:IZMO films on the heat‐sensitive flexible fluorinated ethylene propylene (FEP) substrates are demonstrated, implying that thermal damages are prevented during the deposition.