In conventional pulsed laser deposition (PLD) technique, plume deflection and composition distribution change with the laser incident direction and pulse energy, then causing uneven film thickness and composition distribution for a multicomponent film and eventually leading to low device quality and low rate of final products. We present a novel method based on PLD for depositing large CIGS films with uniform thickness and stoichiometry. By oscillating a mirror placed coaxially with the incident laser beam, the laser's focus is scanned across the rotating target surface. This arrangement maintains a constant reflectance and optical distance, ensuring that a consistent energy density is delivered to the target surface by each laser pulse. Scanning the laser spot across the target suppresses the formation of micro-columns, and thus the plume deflection effect that reduces film uniformity in conventional PLD technique is eliminated. This coaxial scanning PLD method is used to deposit a CIGS film, 500 nm thick, with thickness uniformity exceeding ±3% within a 5 cm diameter, and exhibiting a highly homogeneous elemental distribution.

针对脉冲激光沉积(PLD)薄膜装置,建立了时间分辨等离子体发射光谱测量系统,在沉积类金刚石(DLC)薄膜时,通过对CII(426.7 nm)和CIII(229.7 nm)的发射谱测量发现,当脉冲激光轰击石墨靶材时,C发射谱强度均随时间变化,表现为由强变弱的时间变化过程,并且与靶材的表面状况有很强的相关性。实验过程中保持激光的脉冲频率和单脉冲能量不变,在石墨靶固定时,碳发射谱强度随时间呈快速下降趋势,当石墨靶旋转时,碳发射谱强度变化较为缓慢。实验发现,CIII 和CII的发射谱强度的比值随时间逐渐增大。