半绝缘ZnSe衬底上的外延双生长ZnSe

目前对ZnSe材料的研究工作不断深入,因为ZnSe是一种有潜力的蓝色发光二极管材料,具有2.67eV的直接带隙。从过去的实践中可以看出。高质量的ZnSe单晶是很难生长的。由于良好的光电器件需要高质量的材料,因此需要有不同的制备方法以获得高质量的ZnSe单晶。除了生长高质量ZnSe体单晶外,也有其它的方法,如GaAs或其它衬底上的ZnSe外延生长也可以用来生长ZnSe光电器件用的外延层。但很少有人用ZnSe衬底来生长外延层。为了更进一步地了     

ALE ZnSe单晶薄膜的PL性质

最近,日本茨木电气技术研究所的 T.Yao 等人第一次报导了用原子层外延方法(ALE)生长的不掺杂 ZnSe 单晶薄膜的光致发光性质。光谱显示出很强的激子发射,并由此说明了薄膜质量。单晶薄膜生长所使用的衬底是(100)取向的 GaAs 片。ALE 生长采用 MBE 设备。     

Ⅱ—Ⅵ族宽带隙半导体的分子束外延

我们用分子束外延法已生长出了ZnSe、ZnTe单晶薄层。外延层的生长速率基本上由分子束流量和衬底温度决定。本文讨论了这种二元化合物的生长速率,包括衬底温度、结晶性及分子束强度,并和实验结果作了比较分析。所获得的生长速率与衬底温度和入射束比的关系能用原子表面覆盖度的动力学方程得到解释。     

Ge衬底上的Ⅱ-Ⅵ族化合物MBE生长研究

本文报道了单晶ZnSe、ZnTe和CdTe薄膜在Ge(100)衬底上的MBE生长,用RHEED观察了其生长规律,并对样品作了X光衍射及SIMS等测试分析。观察到衬底与外延层之间存在晶向偏角。对这一现象进行了理论解释。     

ZnCl2掺杂n型ZnSe的分子束外延生长

利用分子束外延(MBE)技术,以5N的ZnCl2作为掺杂源,在半绝缘GaAs (001)衬底上异质外延生长ZnSe:Cl单晶薄膜.研究发现,掺入ZnCl2后,ZnSe外延层的结晶质量和表面形貌与本征ZnSe外延层相比变差,双晶X射线摇摆曲线(DCXRC)的ZnSe (004)衍射峰半峰宽(FWHM)从432 arcsec增大到529 arcsec,表面均方根粗糙度(RMS)从3.00 nm增大到3.70nm.当ZnCl2掺杂源炉的温度为170℃时,ZnSe样品的载流子浓度达到1.238×1019 cm-3,可以满足结型器件制作和隧道结材料设计的要求.     

用MBE制作ZnSe电流限制区的隐埋顶层平面条型(BCP)GaAlAs激光器

我们已经研制成功一种新型结构的GaAlAs可见光激光器,叫做隐埋顶层平面条型(BCP)激光器。这种激光器是用分子束外延(MBE),在复盖层上生长了一层外延ZnSe半绝缘层,并在其上留下一笮条区作为电流限制。图1是GaAlAs BCP激光器的结构示意图。其制作程序如下:在具有1.5μm深槽n型GaAs衬底上用一般的LPE生长了GaAlAs/GaAs DH结之后,第四层(P-GaAs,顶层)是通过SiO_2掩膜腐蚀成3—5μm的条宽的台面。然后,在用MBE晶片上外延一层与顶层同样厚的ZnSe半绝缘层。这种工艺能够在P型GaAlAs复盖层上生长出镜面的ZnSe     

晶格错合(Lattice Misfit)对在GaAs衬底上用原子层外延方法生长的ZnSe晶格参数和光致发光性质的影响

研究了晶格错合对在 GaAs 衬底上用原子层外延方法生长的 ZnSe 薄膜的品格参数和光致发光性质的影响。并观察到厚度小于0.17μm 的 ZnSe 外延层受到完全的四方畸变,而厚度大于0.17μm 的外延层所受到的错合应力则有所减轻。在假定外延层受到完全四方畸变的情况下,外延层中的剩余应力为1.84×10~9dyn/em~2。薄的外延层显示出自由激子辐射和深中心辐射,而厚的外延层则显示出一个主要的与施主相联系的束缚激子辐射和一个弱的深中心辐射。     

在GaAs(100)ZnSe(110)衬底上VPE生长ZnSe薄膜

用高纯度Zn和Se做原材料研究了在GaAs(100)和ZnSe(110)衬底上外延生长ZnSe薄膜.实验是在723和873K下进行的,用光致发光测量、二次离子值谱仪(SIMS)、椭圆对称分析和光学显微镜观察对生长的薄膜进行了测量分析,在Zn和Se的输运比接近1的条件下获得了最佳外延生长膜.对异质外延膜的SIMS分析表明主要受主型杂质最Li和Na.同时,发现在相同生长条件下,与在GaAs衬底上生长的薄膜相比,在高纯ZnSe衬底上外延生长薄膜的PL特性有所改进。值得注意的是衬底纯度对ZnSe衬底上生长薄膜的纯度有很大影响。     

外延生长ZnSe/GaAs中剩余应力对激子发光线劈裂的影响

宽禁带Ⅱ—Ⅵ族化合物,例如 ZnSe 和ZnS 是用于发蓝光的光电子学器件的有前景的材料,但却很难实现对 p—型电导的控制,这主要是生长在不同衬底材料上的外延层内的晶格失配导致的晶格缺陷所致。本文报导的是 GaAs 衬底上生长的 ZnSe外延层中剩余应力的实验结果,其中也考虑     

PbS分子束外延

本文介绍了一种自行设计的、能连续制备多层外延膜的简易分子束外延装置,并用此装置在Pb_(0.8)Sn_(0.2)Te衬底上生长了PbS单晶薄膜。利用扫描电镜、X-射线分析,红外反射光谱等检测手段,对单晶膜的表面形态及结晶质量进行了观察和测试分析。     

Deep level electronic structure of ZnSe/GaAs heterostructures

We performed 1—2 keVcathodoluminescence measurements and He-Ne and HeCd excited photoluminescence studies of ZnSe/GaAs( 100) heterostructures grown by molecular beam epitaxy. Our goal was to investigate the deep level electronic structure and its connection with the heterojunction band offsets. We observed novel deep level emission features at 0.8, 0.98, 1.14, and 1.3 eV which are characteristic of the ZnSe overlayer and independent in energy of overlayer thickness. The corresponding deep levels lie far below those of the near-bandedge features commonly used to characterize the ZnSe crystal quality. The relative intensity and spatial distribution of the deep level emission was found to be strongly affected by the Zn/Se atomic flux ratio employed during ZnSe growth. The same flux ratio has been shown to influence both the quality of the ZnSe overlayer and the band offset in ZnSe/GaAs heterojunctions. In heterostructures fabricated in Se-rich growth conditions, that minimize the valence band offset and the concentration of Se vacancies, the dominant deep level emission is at 1.3 eV. For heterostructures fabricated in Zn-rich growth conditions, emission by multiple levels at 0.88,0.98, and 1.14 eV dominates. The spectral energies and intensities of deep level transitions reported here provide a characteristic indicator of ZnSe epilayer stoichiometry and near-interface defect densities.     

ZnSe单晶的热壁外延生长(英文)

We have successfully grown a ZnSe single crystal film on GaAs(100) by hoi wall epitaxy. We confirmed that the epilayer is ZnSe single crystal from the analysis of scanning eletron microscopy and X-ray diffraction. The strong near-band-edge emission is found in the PL spectra and the Es-band related to free exiton is also very strong. They are much stronger than the deep center band emission, which shows the perfection of the epilayer. We have also studied the ZnSe/GaAs interface by AES and XPS.     

ZnSe heteroepitaxy on GaAs (110) substrate

ZnSe heteroepitaxial layers have been grown on GaAs (100), (110) on axis, and (110) 6° miscut substrates by molecular beam epitaxy. ZnSe on GaAs (110) shows smooth and featureless spectra from Rutherford backscattering channeling measurements taken along major crystalline directions, whereas ZnSe on GaAs (100) without pre-growth treatments exhibit large interface disorder in channeling spectra. ZnSe films grown on GaAs (110) on axis show facet formation over a wide range of growth conditions. The use of (110) 6° miscut substrates is shown to suppress facet formation; and under the correct growth conditions, facet-free surfaces are achieved. Etch pit density measurements give dislocation densities for ZnSe epitaxial layers grown on GaAs (100), (110) on axis, and (110) 6° miscut substrates of 10⁷/cm², 3 × 10⁵/cm² and 5 × 10⁴/cm², respectively. These results suggest that with further improvements to ZnSe growth on GaAs (110)-off substrates it may be possible to fabricate defect free ZnSe based laser devices.     

Study and fabrication of PIN photodiode by using ZnSe/PS/Sistructure

In this experiment, the PIN photodiode by using ZnSe/porous Si/Si structure was investigated. The single crystal ZnSe epilayer is successfully grown on porous silicon substrate with CVD system. Indium is as a dopant to reduce the resistivity of ZnSe intrinsic layer. To control the different thickness of n-ZnSe layer will change the photocurrent and responsivity of the ZnSe PIN diode. The best diffusion conditions are diffusion temperature of 300°C and driving time of 30 min. The responsivity of device is 0.03 A/W. In addition, the dark current of the photodiode is near zero     

Epitaxial Growth of Large‐Scale Orthorhombic CsPbBr3 Perovskite Thin Films with Anisotropic Photoresponse Property

Inorganic cesium lead halide perovskite (CsPbX₃, X = Cl, Br, I) is a promising material for developing novel electronic and optoelectronic devices. Despite the substantial progress that has been made in the development of large perovskite single crystals, the fabrication of high‐quality 2D perovskite single‐crystal films, especially perovskite with a low symmetry, still remains a challenge. Herein, large‐scale orthorhombic CsPbBr₃ single‐crystal thin films on zinc‐blende ZnSe crystals are synthesized via vapor‐phase epitaxy. Structural characterizations reveal a “CsPbBr₃(110)//ZnSe(100), CsPbBr₃[?110]//ZnSe[001] and CsPbBr₃[001]//ZnSe[010]” heteroepitaxial relationship between the covering CsPbBr₃ layer and the ZnSe growth substrate. It is exciting that the epitaxial film presents an in‐plane anisotropic absorption property from 350 to 535 nm and polarization‐dependent photoluminescence. Photodetectors based on the epitaxial film exhibit a high photoresponsivity of 200 A W^?1, a large on/off current ratio exceeding 10⁴, a fast photoresponse time of about 20 ms, and good repeatability at room temperature. Importantly, a strong polarization‐dependent photoresponse is also found on the device fabricated using the epitaxial CsPbBr₃ film, making the orthorhombic perovskite promising building blocks for optoelectronic devices featured with anisotropy.     

Growth of P-type Znse by metalorganic molecular beam epitaxy using metal Zn and dimethylselenide

This paper describes metalorganic molecular beam epitaxy (MOMBE) of p-type ZnSe using metal zinc, pre-cracked metalorganic dimethylselenide, and microwave-excited nitrogen plasma as sources. Optical, structural, and electrical properties of the p-type ZnSe layers have been investigated. At present, maximum net acceptor concentration N_a-N_d is 3 x 10¹⁷ cm^-3 without any post-growth annealing. This is the highest acceptor concentration ever reported for MOMBEgrown p-type ZnSe doped with nitrogen plasma, but photoluminescence and deep level transient spectroscopy suggest that acceptors are highly compensated and the reduction of compensating defects is a key to further increase the acceptor concentration.     

MO-PPV/ZnSe量子点复合材料的制备及光致发光特性研究

采用水相法制备了颗粒尺寸为3.75nm的硒化锌(ZnSe)量子点,采用表面活性剂将ZnSe量子点转移到有机相聚(2-甲氧基-5-辛氧基)对苯乙炔(MO-PPV)中,获得了MO-PPV/ZnSe复合材料。通过对MO-PPV和ZnSe量子点的吸收光谱(ABS)和光致发光(PL)光谱的研究发现,随着ZnSe量子点掺杂浓度的提高,复合材料的发光强度明显增强,发光峰位置出现了蓝移。当ZnSe∶MO-PPV的质量比为1∶0.181时,发光峰位置蓝移10nm。结果表明,MO-PPV与ZnSe量子点之间存在着能量传递,这是导致MO-PPV/ZnSe量子点复合材料具有PL增强的重要原因。     

Surface treatment of znse substrate and homoepitaxy of znse

High quality ZnSe(100) substrates have been used for homoepitaxial growth by molecular beam epitaxy. A chemical pretreatment suitable for ZnSe substrate preparation is determined from x-ray photoemission spectroscopy studies. Thermal cleaning processes for the ZnSe(100) surface were investigated by insitu reflection high energy electron diffraction and the surface phase diagram for ZnSe(100) was obtained for the first time. The low temperature photoluminescence spectra recorded from homoepitaxial layers exhibit unsplit free and bound exciton transitions with strong intensities. The full widths at half maximum of the (400) x-ray diffraction spectra for ZnSe homoepitaxial layer were 17≈31 arcsec.     

3.77-5.05-/spl mu/m tunable solid-state lasers based on Fe/sup 2+/-doped ZnSe crystals operating at low and room temperatures

Spectroscopic properties and lasing of Fe:ZnSe and co-doped Fe:Cr:ZnSe crystals in the mid-infrared spectral range were studied at room and low temperatures. Using a free-running Er:YAG laser as a pump source, the output energy of the thermoelectrically cooled Fe:ZnSe laser was 142 mJ with 30% slope efficiency at T=220 K. Passive Q-switched oscillation of Er:YAG laser with Fe:ZnSe crystal was demonstrated and used as a pump source for a Fe:ZnSe laser system. Room-temperature (RT) gain-switched lasing of Fe:ZnSe was achieved in microchip and selective cavity configurations using Q-switched Er:YAG and Raman-shifted Nd:YAG lasers as pump sources. The microchip laser threshold of 100 mJ/cm/sup 2/ was demonstrated using a Fe:ZnSe crystal without any reflection coatings. A slope efficiency of 13%, oscillation threshold of 1.3 mJ, and tunable oscillation of Fe:ZnSe laser systems over 3.95-5.05 /spl mu/m spectral range were realized at RT.     

A Precursor‐Based Route to ZnSe Nanowire Bundles

A large number of one‐dimensional bundles of ZnSe nanowires with diameters ranging from 15–20 nm and lengths of up to tens of micrometers have been prepared via the thermal treatment of a ribbon‐like precursor (ZnSe·3ethylenediamine), which has been synthesized by a mixed solvothermal route, in an argon atmosphere. The as‐obtained precursor has been characterized by powder X‐ray diffraction (XRD), transmission electron microscopy (TEM), IR spectroscopy, thermogravimetric analysis, and elemental analysis. XRD and high‐resolution TEM characterization reveal that the as‐synthesized ZnSe nanowires have the single‐crystal hexagonal wurtzite structure with the [001] growth direction. The surface chemical composition of ZnSe nanowires has been studied by X‐ray photoelectron spectroscopy. The cooperative action of the mixed solvents may be responsible for the formation of the morphology of the resulting products. Room‐temperature photoluminescence measurements indicate the as‐grown ZnSe nanostructures have a strong emission peak centered at 587 nm and two weak emission peaks centered at 435 and 462 nm. The strong emission from the ZnSe nanostructures reveals their potential as building blocks for optoelectronic devices.