温度对Si上MOCVD-ZnO成核与薄膜生长特性的影响

采用金属有机化学气相沉积(MOCVD)方法在Si衬底上进行了ZnO的成核与薄膜生长研究。ZnO薄膜的形貌和结晶特性由成核和后期生长过程共同决定,初期成核温度决定了其尺寸和密度,进而影响后期ZnO主层的生长行为,但由于高温对后期ZnO纳米柱横向生长的抑制,纳米柱的尺寸并没有因为成核尺寸的增大而变大,因此在560℃得到了晶柱尺寸最大、密度最小的ZnO薄膜。最后通过改变成核温度,优化了ZnO外延膜的结晶质量。     

ZnO-Based Transparent Thin-Film Transistors with MgO Gate Dielectric Grown by in-situ MOCVD

ZnO transparent thin-film transistors with MgO gate dielectric were fabricated by in-situ metal organic chemicM vapor deposition （MOCVD） technology. We used an uninterrupted growth method to simplify the fabrication steps and to avoid the unexpectable contaminating during epitaxy process. MgO layer is helpful to reduce the gate leakage current, as well as to achieve high transparency in visible light band, due to the wide band gap （7. 7eV） and high dielectric constant （9.8）. The XRD measurement indicates that the ZnO layer has high crystal quality. The field effect mobility and the on/off current ratio of the device is 2.69cm^2V^-1s^-1 and - 1 × 10^4, respectively.     

MOCVD法制备的p-ZnO/n-SiC 异质结器件及其电致发光性能

采用光辅助金属有机化学汽相沉积(PA-MOCVD)法在n-SiC(6H)衬底上制备出As掺杂的p型ZnO薄膜,并制备出相应的p-ZnO:As/n-SiC异质结器件。X射线衍射(XRD)和光致发光(PL)测试表明,ZnO薄膜具有较好的结构和光学特性。电流-电压(I-V)测试结果表明,该型异质结器件具有良好的整流特性,开启电压为5.0 V,反向击穿电压约为-13 V。正向偏压下,器件的电致发光(EL)谱表现出两个分别位于紫外和可见光区域的发光峰,通过和ZnO、SiC的PL谱对照,证实异质结器件的发光峰来源于ZnO侧的辐射复合。     

利用MOCVD技术生长As掺杂的p-ZnMgO薄膜

利用GaAs夹层掺杂的新方法,采用金属有机化学气相沉积(MOVCD)技术,通过控制生长温度,在蓝宝石衬底上成功制备出As掺杂的p型ZnMgO薄膜.利用X射线衍射分析(XRD)、霍尔效应测试和光致发光(PL)谱等表征方法对薄膜的晶体结构、电学性能和光学特性进行分析.结果表明:高温生长的ZnMgO薄膜具有良好的c轴取向性;...     

Low-dimensional phases engineering for improving the emission efficiency and stability of quasi-2D perovskite films

The two-dimensional (2D) Ruddlesden-Popper-type perovskites, possessing tunable bandgap, narrow light emission, strong quantum confinement effect, as well as a simple preparation method, are identified as a new generation of candidate materials for efficient light-emitting diodes. However, the preparation of high-quality quasi-2D perovskite films is still a challenge currently, such as the severe mixing of phases and a high density of defects within the films, impeding the further promotion of device performance. Here, we prepared the quasi-2D PEA₂MA_n-1Pb_nBr_3n+1 perovskite films by a modified spin-coating method, and the phases with large bandgap were effectively suppressed by the vacuum evaporation treatment. We systematically investigated the optical properties and stability of the optimized films, and the photoluminescence (PL) quantum yield of the treated films was enhanced from 23% to 45%. We also studied the emission mechanisms by temperature-dependent PL spectra. Moreover, the stability of films against moisture, ultraviolet light, and heat was also greatly improved.     

Au层退火温度对ZnO/Au/ZnO多层膜的结构、光学及电学性质的影响

采用金属有机化学气相沉积(MOCVD)技术在蓝宝石衬底上制备出晶体质量较好的透明导电的ZnO/Au/ZnO(ZAZ)多层膜,其中,Au夹层是通过射频磁控溅射的方法获得。通过对Au夹层进行不同温度的退火处理,研究了Au层退火温度对ZAZ多层膜的结构特性、电学性能和光学特性的影响。利用原子力显微镜(AFM)、扫描电子显微镜(SEM)、X射线衍射(XRD)仪、霍尔效应测试和透射谱分析等测试手段对ZAZ多层膜的性质进行了分析。测试结果表明,在200 ℃下对Au夹层进行快速退火处理,多层膜的结构、电学和光学性质达到最优,表面等离子体效应也更明显。其中,XRD(002)衍射峰的半高宽为0.14°,电阻率为2.7×10^-3 Ω·cm,载流子浓度为1.07×10²⁰ cm^-3,可见光区平均透过率为75.3%。     

Electrically Pumped Ultraviolet Random Lasing from p-ZnO：As Based on p-ZnO/N-GaN Heterojunction

p-ZnO：As is prepared by the GaAs interlayer doping method. The potential applications of p-ZnO：As are evaluated by applying it into the construction of a p-ZnO/n-GaN heterojunction, though its hall, electrochemical capacitance-voltage and photoluminescence results show a hole concentration at the level of -10^17 cm-3 and a good optical quality. Ultraviolet random lasing is detected from the studied device under forward bias. Specific lasing modes are confirmed to originate from p-ZnO：As by further introducing the p-ZnO/MgO/n-GaN het- erostructure. The resulting random lasing phenomena demonstrate the promising prospects in device application of p-ZnO：As fabricated by using our methods.     

Uniform light emission from electrically driven plasmonic grating using multilayer tunneling barriers

Light emission by inelastic tunneling(LEIT)from a metal-insulator-metal tunnel junction is an ultrafast emission process.It is a promising platform for ultrafast transduction from electrical signal to optical signal on integrated circuits.However,existing procedures of fabricating LEIT devices usually involve both top-down and bottom-up techniques,which reduces its compatibility with the modern microfabrication streamline and limits its potential applications in industrial scale-up.Here in this work,we lift these restrictions by using a multilayer insulator grown by atomic layer deposition as the tunnel barrier.For the first time,we fabricate an LEIT device fully by microfabrication techniques and show a stable performance under ambient conditions.Uniform electroluminescence is observed over the entire active region,with the emission spectrum shaped by metallic grating plasmons.The introduction of a multilayer insulator into the LEIT can provide an additional degree of freedom for engineering the energy band landscape of the tunnel barrier.The presented scheme of preparing a stable ultrathin tunnel barrier may also find some applications in a wide range of integrated optoelectronic devices.     

ZnO-based deep-ultraviolet light-emitting devices

Deep-ultraviolet(DUV) light-emitting devices(LEDs) have a variety of potential applications.Zinc-oxide-based materials,which have wide bandgap and large exciton binding energy,have potential applications in high-performance DUV LEDs.To realize such optoelectronic devices,the modulation of the bandgap is required.This has been demonstrated by the developments of Mg_xZn_(1-x)O and Be_xZn_(1-x)O alloys for the larger bandgap materials.Many efforts have been made to obtain DUV LEDs,and promising successes have been achieved continuously.In this article,we review the recent progress of and problems encountered in the research of ZnO-based DUV LEDs.     

金属有机化学气相沉积法制备ZnO和ZnO∶Ni薄膜及其特性分析

采用金属有机化学气相沉积法制备了ZnO和ZnO∶Ni薄膜,并对它们的结构、光学和电学特性进行了对比研究.通过扫描电子显微镜( SEM)和X射线衍射(XRD)对薄膜的表面形貌和晶体结构进行了分析,结果表明,Ni元素的掺杂虽然降低了薄膜的晶体质量,但并未改变ZnO的纤锌矿结构.通过紫外-可见分光光度计对薄膜的光学特性进行了...