Preparation and Characterization of Radio Frequency Sputtered Delafossite p-type Copper Gallium Oxide (p-CuGaO₂) Thin Films

Abstract

In this research, CuGaO2 thin films were prepared on quartz substrates by a radio frequency magnetron sputtering technique at 400℃ followed by subsequent annealing in N2 ambience. The effects of annealing temperature on structural, morphological, optical, and electrical properties of CuGaO2 thin films is reported. X-ray Diffraction (XRD) analysis confirmed the presence of single phase CuGaO2 in the film annealed at 900℃. Near stoichiometric composition ratio of Cu:Ga (1:1.08) was identified in the film annealed at 900℃. Field emission scanning electron microscopy showed an increase in the grain size with increase in annealing temperature. A UV-Vis spectrophotometer was used to perform optical studies in the 200-800nm wavelength region on all films. The optical bandgap was calculated from the transmission studies and was found to be in the range of 2.77 to 3.43 eV. The films annealed at temperatures 800℃ and above were found to be p-type. The lowest resistivity value of 230 Ω-cm was achieved for the film annealed at 900℃.

Preparation and Characterization of p-Type Copper Gallium Oxide (CuGaO2) Thin Films by Dual Sputtering Using Cu and Ga2O3 Targets

“…[5][6][7] Copper-based delafossite materials are p-type TCOs garnering much attention due to their wide bandgap. 8,9 The chemical formula for Cu-based delafossite materials is CuMO 2 , where Cu is a positive monovalent cation (Cu + ), M is a trivalent cation such as Al 3+ , Ga 3+ , and In 3+ , and oxygen is the negative divalent anion (O 2− ). 3 Among all the Cu-based delafossite materials, CuGaO 2 is being extensively researched owing to its noteworthy optical, 10,11 electrical, 10,11 and photovoltaic properties.…”

“…[14][15][16] Due to these excellent properties, CuGaO 2 finds applications in solar cells, [17][18][19] photocatalysis, 20,21 electrolysis of water for oxygen, and hydrogen evolution for renewable energy. 12,22 CuGaO 2 thin films have been prepared by a variety of techniques such as sputtering, 3,8 pulsed laser deposition, 23,24 hydrothermal method, 12,21 sol-gel deposition, 3,9 and spin coating. 1 Among all the aforementioned techniques, RF magnetron sputtering is an established method to obtain thin films with uniformity and homogeneity.…”

Investigation on the Intermixing of Cu and In Layers for the Formation of Cu2In2O5 Thin Films

“…15 There has been a recent spike in research interest in synthesizing p-type conducting copper indium oxide and copper gallium oxide TCO. [16][17][18][19][20][21][22][23][24][25][26][27][28] The two phases of Cu-In-based oxide include CuInO 2 and Cu 2 In 2 O 5 . Even though there has been a lot of research focused on developing CuInO 2 thin films, investigation geared towards developing a singlephase Cu 2 In 2 O 5 thin films has been lacking.…”

Gallium Oxide Nanostructures: A Review of Synthesis, Properties and Applications

“…Magnetron sputtering is another popular process for the synthesis of gallium oxide employed by many researchers [92][93][94][95]. The process requires a chamber and an environment that would facilitate the formation of gallium oxide.…”