Available online at www.sciencedirect.com Optics & Laser Technology 35 (2003) 475–480 www.elsevier.com/locate/optlastec EmissionpropertiesoflaserablationofSnO 2 :Sbtransparentconducting lmandKTiOPO 4 crystal MinjuYing a ; * ,YueyuanXia b ,YumingSun a ,YuchenMa a ,MingwenZhao b , XiaotaoHao b ,XiangdongLiu b a Department of Optoelectronics, Shandong University, Jinan, Shandong 250100, People’s Republic of China b Department of Physics, Shandong University, Jinan, Shandong 250100, People’s Republic of China Received 20 May 2002; accepted 4 March 2003 Abstract Optical emission spectra of Nd:YAG laser ablation of KTiOPO4 (KTP) crystal and SnO2:Sb transparent conducting thin lm were recorded and analyzed in vacuum and in air. The integral intensities of spectral lines from laser-ablated KTP crystal were obtained as functionsofdistancefromthetargetsurfaceandlaserpowerdensityinvacuumandinair.Theambientgaseectsonpulsedlaserablation oftargetwerediscussed.WealsoperformedlaserablationofSnO2:Sbtransparentconductingthinlminairandtheelectrontemperature and full-width at half-maximum (FWHM) of atomic and ionic spectral lines in the plasma were quantied using Boltzmann plot method and Lorentzian t, respectively. Integral intensities of atomic and ionic Sn spectral lines were also obtained as functions of distance from the target surface and laser irradiance. The intensity ratio of ionic and atomic Sn spectral lines as a function of laser power density was gotwhichgivessomeinformationaboutthevariationofionizationratiowithlaserirradianceintheplasmaproducedbyhigh-powerlaser. ? 2003 Elsevier Science Ltd. All rights reserved. Keywords: Laser ablation; Optical emission spectroscopy; Plasma diagnosis 1. Introduction Laserablationofmaterialshasbeentheobjectofintensive theoretical and experimental study since it is important for both the basic understanding of laser–material interactions and many practical applications, such as pulsed laser depo- sition (PLD) for thin lm growth. When high-power laser with density exceeds the breakdown threshold of the ma- terial, the surface of the irradiated material instantaneously reaches a temperature higher than the material’s vaporiza- tiontemperatureduetophotonandmulti-photonabsorption andotherabsorptionmechanismsandthelaserenergyisab- sorbedrapidly,causingexplosionofthesurfaceandforma- tionofdenseplasma[1,2].Analysisoftheresultantplasma is helpful for understanding the complex ablation process and optimizing the experimental conditions in practical ap- plications [3].Amongtheplasmaanalysistechniques,opti- cal emission spectroscopy (OES) allows us to monitor the ∗ Corresponding author. Tel.: +86-5318364655; fax: +86-5318565167. E-mail address: minjuying@163.com (M. Ying). ablation process real time and in situ without introducing disturbingatall.Infact,OEShasbeenwidelyusedtoana- lyze the qualitative and quantitative composition of plasma produced by laser ablation of various materials [4–6], and to monitor and optimize the pulsed laser deposition pro- cess, such as the deposition of ITO transparent conducting lm[3]. KTiOPO 4 isawell-knownmaterialwithexcellentnonlin- earopticalpropertiesformanyapplications,someofwhich may require the production of high-quality thin lms. Al- though PLD has proven to be one of the most successful techniques in growing complex oxide lms [7], the opti- calparametersforlmspreparedbyablationofcrystalsare notwellestablished[8,9].Transparentconductinglmsare widely used in optoelectronic devices, such as solar cells, electro-opticalmodulators,andliquidcrystaldisplay(LCD) because they are both highly transparent in visible light spectrum and have nearly metallic conductivity. Compared with ITO and ZnO lms, SnO 2 : Sb has better thermal and chemical stability and is nding more and more great use now [10,11]. The above lms are typically fabricated by 0030-3992/03/$-see front matter ? 2003 Elsevier Science Ltd. All rights reserved. doi:10.1016/S0030-3992(03)00061-6