Pulsed Laser Deposition Of Thin Films Of Zno Fluorescence

AbstractField emission display (FED) is given mucb attentions by mauy researckers' fOr its advautages such as high luminance, thin structure, Iow I,ower.' consumption, and kigh visual propcrty TO tmake Itigh quality FED, not onIysuperior cathode but aIso matching nuorescent anode and ltigh sealcd vacuum. technique are needed. Howeven conventionalipowder phosphor screcns can notmeet with the operating conditions in FED.TO oPtimise anode of FED, the zinc oxidc (ZnO) Iumincsccnt tkin films wcreprepared by pulsed lascr deposition (PLD) through varying the laser nucucc andoxygcn pressure,of dcpositcd ckamber. Wc also studied thc nlm8 by anncalingand coating them. The main rcscarch results of our experiments are described a8fOllows.The ZnO thin films werc prepared with diffcrcnt lascr flucnce and otherconstant parameters. The results show that the films dcposited at low flucncchave bcttcr crystal structure and better luminescent quality We conclude that itdcpends on thc number of dislocations, grain houndaries and other dcfectS, i.c.non-radiational combination centers, in the luminescent thin nlms. Morenon-radiational combination ccnters wcre occurrcd in the films prepared withhigh laser nuence, less and supcrior in the contrary.Wc investigate thc effects of thc oxygen prcssurc on the crystal andIuminescent quality of the ZnO Iuminescent thin fiIms hy depositing films atvariablc oxygcn pressure with other maintained paramctcrs. The findingsindicate tbat there is a preferentiaI value during 104~10-l TOrr which makcs ZnOlumincscent thin films to have better crystal structurc and bcttcr lumincsccntquaIity So wc learned tkat though the improvcment of the films structurc byrising oxygcn pressure is at thc cxpcnsc of reducing the lumincscent centcrs, wccan gct thc prefercntial luminesccnt centers in thc films at an appropriate onygcn xprcssure.lTwo kinds of ZnO luminescent thin films were deposited at different substrate temperature and post-annealing in the air respectively. We found that the crystal of the films get better after annealing, the luminance of the film prepared at room temperature obviously improved while that of the film deposited at higher temperature decreased. This shows that annealing can reduce the number of defects forming well energy level more in the film prepared at room temperature and increase its luminance, but reduce the luminescent centers in that deposited at higher temperature and decrease its luminescent quality.Al films on the top of the luminescent thin films were prepared by dual-target. By comparision the luminance of the ZnO films which are the samples made before and after Al film deposition, it is found that the luminance of ZnO films with Al film is enhanced considerably.The paper includes 4 chapters. Chap. 1 describes and reviewes the present research state of luminescent thin film which is to be anode of field emission display. The luminescent mechanism and the methods of preparing and testing luminescent thin films are discussed in Chap. 2. Chap. 3 introduces the PLD of ZnO luminescent thin films and Chap. 4 draws some conclusions.