关键词: β-Ga₂O₃, 4H-SiC衬底, 脉冲激光沉积, 生长温度, 异质结太阳能电池, 光电转换效率

Abstract: In this paper, β-Ga₂O₃ films grown preferentially along (403) were prepared on p-type 4H-SiC substrate by pulsed laser deposition (PLD). The results show that the growth temperature has an important influence on the morphology, structure, composition and growth mechanism of β-Ga₂O₃ film. When the growth temperature increases from 300 ℃ to 500 ℃, the crystalline quality of the β-Ga₂O₃ film raises with the increasing temperature, but when the temperature further increases to 600 ℃, the crystalline quality of the thin film becomes worse. It was tried to explain that the kinetic energy of atoms deposited on the substrate increases with the increase of growth temperature below 500 ℃, leading to easier migration of atoms, finally, the film is grown in two-dimensional mode and has smaller roughness as measured by AFM. However, when the temperature further increases to 600 ℃, the two-dimensional growth mode is changed to three-dimensional island shape, because of the difference in thermal expansion coefficient between 4H-SiC substrate and β-Ga₂O₃ thin film, resulted in the larger roughness. The photovoltaic conversion efficiency of heterojunction solar cell based on p-4H-SiC/n-β-Ga₂O₃ reaches 3.43% under standard test conditions.

Key words: β-Ga₂O₃, 4H-SiC substrate, pulsed laser deposition, growth temperature, heterojunction solar cell, photovoltaic conversion efficiency