ZnO薄膜的光抽运紫外激射  

Optically Pumped Ultraviolet Lasing Property of ZnO Film

作　　者：刘大力[1] 杜国同[1] 张源涛[1] 王新强[1] 杨天鹏[1] 杨晓天[1] 赵佰军[1] 杨洪军[1] 刘博阳[1] 张景林[1] 

机构地区：[1]吉林大学电子科学与工程学院集成光电子学国家重点实验室,吉林长春130023

出　　处：《发光学报》2004年第4期389-392,共4页Chinese Journal of Luminescence

基　　金：国家"8 63"( 2 0 0 1AA3 1113 0 ) ;国家自然科学基金 ( 60 1770 0 7;60 1760 2 6)资助项目

摘　　要：采用等离子体增强MOCVD方法生长出高质量的ZnO薄膜 ,并观察到了ZnO薄膜的光抽运紫外激射现象。在不同激发强度下进行了光荧光谱测量 ,发现紫外发光强度随着激发光强度的增加呈直线增强 ,证明此紫外发光峰来源于带边自由激子辐射复合。激发的激光器为 3倍频YAG激光器 ,脉宽 15ps,每秒 10个脉冲。抽运光达到样品的光斑直径约为 2 5 μm ,激射阈值为 0 .2 8μJ ,利用光纤连接到CCD来探测接收激射光。在 385～ 390nm之间的激射峰 ,其半峰全宽为 0 .0 3nm。所观察到的激射没有固定的方向 ,也就是说是往各个方向发射的。对于ZnO薄膜 ,由于我们并没有制作通常激光器的谐振腔 。Recently much attention has been paid to short wavelength lasers for use in high density information storage. It is widely accepted that ZnO is one of the most promising materials for producing an ultraviolet laser at room temperature due to its wide direct band gap (E_g=3.37 eV) and large excitonic binding energy of 60 meV. It has potential uses in optoelectronical systems such as light emitting diodes(LEDs), photodetectors, electroluminecence devices and solar cells. To obtain high quality ZnO thin films a variety of techniques may be used such as molecular beam epitaxy(MBE), metal organic chemical vapor deposition(MOCVD), magnetron sputtering, pulsed laser deposition, and so on. Among them, MOCVD provides the advantage of growing high-quality films due to its versatility in controlling the various thermodynamic interactions. ZnO has not only the same crystal structure as GaN, but also a larger exciton binding energy of 60 meV, which is 2.4 times that of GaN. This indicates that ZnO should be the most potential material to realize the next generation UV semiconductor laser. High quality ZnO films were deposited on c-Al_2O_3 substrate by the plasma-assisted metal-organic chemical vapor deposition. Strong optically pumped ultraviolet (UV) emission was observed. PL spectra under different excitation powers were performed. The PL intensity as a function of the excitation power, it is obvious that the PL intensity is linearly dependent on the excitation power. This indicates that the dominant photoluminescence of the sample should be the excitonic radiative recombination at room temperature.Optically pumped UV lasing spectrum of ZnO film was observed. The samples were optically pumped by a frequency-tripled mode-locked Nd∶YAG laser 355 nm emission, with 10 Hz repetition rate, and 15 ps pulse width. The pump beam was focused to a spot with diameter of about 25 μm on the surface of ZnO film. The threshold of lasing was as low as 0.28 μJ. From the lasing spectrum, we could find that the lasing peak has much narrow

关 键 词：金属有机化学气相沉积方法 ZNO薄膜 光抽运紫外激射 

分 类 号：O472.3[理学—半导体物理]