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1.
利用卢瑟福背散射/沟道技术对射频等离子体辅助分子束外延法生长在蓝宝石衬底上的ZnO/Zn0.9Mg0.1O/ZnO异质结进行了组分分析,并得到了异质结弹性应变随深度的变化,应变由界面向表面逐渐释放,并由负变正,且在ZnO与Zn0.9Mg0.1O界面处轻微增大.负的应变是由于ZnO与衬底的晶格失配和热失配,而逐渐变为正值是Zn0.9Mg0.1O与ZnO的晶格常数差异及弹性应变的
关键词:
异质结
卢瑟福背散射/沟道
弹性应变
ZnMgO 相似文献
2.
在c-plane面蓝宝石衬底上生长了ZnO/Zn0.85Mg0.15O非对称双量子阱,其内量子效率相对于对称量子阱有了显著的提高。ZnO/Zn0.85Mg0.15O的10周期对称量子阱和5周期非对称双量子阱都是利用等离子体辅助分子束外延技术制备的。ZnO/Zn0.85Mg0.15O非对称双量子阱的内量子效率提高至对称阱的1.56倍。时间分辨光谱和光致发光谱测试结果证实,在ZnO/Zn0.85Mg0.15O非对称双量子阱中存在从窄阱到宽阱的激子隧穿过程,这是内量子效率提高的主要原因。 相似文献
3.
利用固源分子束外延技术,在In0.15Ga0.85As/GaAs量子阱生长了两个InAs/In0.15Ga0.85As量子点(DWELL)样品.通过改变其中一个InAs DWELL样品中的In0.15Ga0.85As阱层的厚度和生长温度,获得了量子点尺寸增大而且尺寸分布更均匀的结果.结合光致发光光谱(PL)和压电调制光谱(PzR)实验结果,发现该样品量子点的光学性质也同时得到
关键词:
合金分解效应
0.15Ga0.85As量子点')" href="#">InAs/In0.15Ga0.85As量子点
光致发光光谱
压电调制光谱 相似文献
4.
采用超声喷雾热分解(Ultrasonic Spray Pyrolysis,USP)方法,以醋酸锌、醋酸镁、醋酸铵、氯化铝的混合水溶液为前驱溶液,在单晶Si(100)衬底上制备了ZnO,Zn0.81Mg0.19O,N-Al共掺杂ZnO和N-Al共掺杂Zn0.81Mg0.19O薄膜。以X射线衍射(XRD)、场发射-扫描电镜(FE-SEM)、霍尔效应(Hall-effect)、光致发光(Photoluminescence,PL)谱等手段研究了薄膜的晶体结构、表面形貌、电学性能、光学性能和带隙变化。电学测试结果表明,未掺杂ZnO及Zn0.81Mg0.19O薄膜为n型导电;而N-Al共掺杂ZnO和N-Al共掺杂Zn0.81Mg0.19O薄膜呈p型导电。Zn0.81Mg0.19O和N-Al共掺杂Zn0.81Mg0.19O(p型)薄膜在维持ZnO纤锌矿结构的前提下,光学带隙随Mg掺杂量增加而增大。初步结果显示,优化工艺参数下通过Mg掺杂制备光学带隙可调的p型Zn0.81Mg0.19O薄膜,对于试制Zn1-xMgxO基同质p-n结、短波长(紫外、深紫外)器件等方面有重要意义。 相似文献
5.
利用固源分子束外延技术,在In0.15Ga0.85As/GaAs量子阱生长了两个InAs/In0.15Ga0.85As量子点(DWELL)样品.通过改变其中一个InAs DWELL样品中的In0.15Ga0.85As阱层的厚度和生长温度,获得了量子点尺寸增大而且尺寸分布更均匀的结果.结合光致发光光谱(PL)和压电调制光谱(PzR)实验结果,发现该样品量子点的光学性质也同时得到了极大的优化.基于有效质量近似的数值计算结果表明:量子点后生长过程中应力导致In0.15Ga0.85As阱层合金分解机理是导致量子点尺寸和光学性质得到优化的主要原因. 相似文献
6.
7.
利用电感耦合等离子体(ICP)装置对分子束外延(MBE)法在Sapphire衬底上生长的Zn1-xMgxO薄膜的Mg组分进行了测试. 经理论分析,得到使用1次和2次检量式所确定的Zn1-xMgxO薄膜中的Mg组分的差异. 将采用1次检量式的ICP测定与EPMA测定结果进行对照,表明当Mg组分x≤0.5时二者的测试结果相当一致,由此证明ICP测试结果的正确性.
关键词:
ZnMgO薄膜
Mg组分
分子束外延(MBE)
电感耦合等离子体(ICP) 相似文献
8.
9.
对一系列δ掺杂浅受主铍(Be)原子的GaAs/AlAs多量子阱和均匀掺杂Be受主的GaAs体材料中Be原子的能级间跃迁进行了光致发光(PL)研究.实验中所用的样品是通过分子束外延技术生长的均匀掺杂Be受主的GaAs外延单层样品和一系列GaAs/AlAs多量子阱样品,并在每量子阱中央进行了Be原子的δ掺杂,量子阱宽度为30 到200 ?.在4.2 K温度下测量了上述系列样品的光致发光谱,清楚地观察到了束缚激子的受主从基态1s3/2(Γ6)到第一激发态
关键词:
量子限制受主
光致发光
多量子阱
δ掺杂 相似文献
10.
采用射频反应磁控溅射的方法,在经过氧化处理的Al2O3(0001)基片上制备了具有良好调制结构的ZnO/MgO多层膜量子阱.利用X射线反射率测量、X射线衍射分析、电子探针显微分析、原子力显微镜、透射光谱以及光致发光光谱等表征技术,研究了ZnO/MgO多量子阱的结构、表面形貌和光致发光等特性.XRD以及扫描的结果表明多层膜样品具有高c轴择优取向并且与蓝宝石基片有良好的外延关系.通过X射线反射率测量的结果得到多量子阱的调制周期,结合电子
关键词:
ZnO/MgO
多量子阱
反应磁控溅射
变温光谱 相似文献
11.
The ZnO/Zn0.85Mg0.15O multiple quantum wells (MQWs) were fabricated on Si(111) substrates by plasma-assisted molecular beam epitaxy (P-MBE) using ZnMgO as buffer layers. The RHEED images indicated that the MQWs were of high quality. The free exciton (FE) emission line originated from the well region and its phonon replicas (FE-1LO, FE-2LO and FE-3LO) were observed in the 86 K photoluminescence (PL) spectrum. Blueshift of the FE line in the MQW sample as compared to that in the ZnO bulk was found at temperatures as high as room temperature. Time-resolved PL study on the FE line showed a fast lifetime of 140 ps. The high quality of the MQW structure was revealed by the observation of the quantum-confinement-induced blueshift and shortened lifetime of the FE emission. 相似文献
12.
A. A. Lotin O. A. Novodvorsky L. S. Parshina E. V. Khaydukov O. D. Khramova V. Ya. Panchenko 《Laser Physics》2011,21(3):582-587
The multiple quantum wells (MQW) Mg0.27Zn0.73O/ZnO have been grown by pulsed laser deposition method with different well width L
w
. The optical and structural characteristics of MQW Mg0.27Zn0.73O/ZnO have been investigated. The quantum confinement effect showing up in the blue shift of exciton peak in low temperature
(8 K) photoluminescence spectra at well width reduction has been studied. It is established that intensity exciton peak I
ex and Einstein’s characteristic temperature Θ
E
increase at reduction of well width L
w
. It is revealed that the discontinuity ratio of conduction and a valence bands in heterostructure Mg0.27Zn0.73O/ZnO is 0.65/0.35 that corresponds to the literature. 相似文献
13.
A. A. Lotin O. A. Novodvorsky L. S. Parshina E. V. Khaydukov D. A. Zuev O. D. Khramova V. Y. Panchenko 《Applied physics. B, Lasers and optics》2011,105(3):565-572
The multiple quantum wells (MQW) Mg0.27Zn0.73O/ZnO have been grown by the pulsed laser deposition method with different well widths L
w
. The interface roughness of quantum wells was inherited from the bottom one and did not exceed 1 nm. We observed the quantum
confinement effect showing up in the blue shift of the exciton peak in the low temperature (8 K) photoluminescence and absorption
spectra at well width reduction. The exciton binding energy of the two-dimensional structures Mg0.27Zn0.73O/ZnO was two times higher in comparison with the bulk ZnO. It has been established that Einstein’s characteristic temperature
Θ
E
sharp increase with reduction of well width L
w
up to L
w
=2.6 nm. It has been revealed that the discontinuity ratio of conduction and valence bands in the heterostructure Mg0.27Zn0.73O/ZnO is 0.65/0.35. We demonstrated the abrupt increase in quantum efficiency at a reduction of the well width that allowed
us to observe the optically excited stimulated emission in ZnO quantum wells with the excitation threshold of ∼210 kW/cm2. 相似文献
14.
W. Chen X. H. Pan H. H. Zhang P. Ding H. P. He J. Y. Huang B. Lu Z. Z. Ye 《Applied Physics A: Materials Science & Processing》2014,115(3):817-821
This work investigates the structural and optical properties of non-polar ZnO/Zn0.81Mg0.19O multiple quantum wells (MQWs), which have been prepared on $r$ -plane sapphire substrates by plasma-assisted molecular beam epitaxy (MBE). The MQWs are ( $11\bar{2}0$ ) oriented ( $a$ -plane) as identified by the X-ray diffraction pattern. Structural properties are anisotropic and surfaces of MQWs show stripes running along the ZnO $c$ -axis direction. Sharp interfaces between the well layers and barrier layers can be clearly resolved by the secondary ion mass spectroscopy (SIMS) analysis. The room-temperature photoluminescence (PL) resulting from the well regions exhibits a significant blueshift with respect to ZnO single layer. Exciton emission in the ZnO QW is resolved into two components in the temperature dependence of the PL spectra. Two types of excitons are responsible for this feature. The excitons trapped by the potential minima dominate at low temperature, and the excitons localized in the “free exciton states” dominate at relatively high temperature. An activation energy of 7.3 meV for quenching of the exciton emission is in good agreement with the transition of the two types of excitons. 相似文献
15.
《Superlattices and Microstructures》1994,16(1):41-45
The dynamics and stimulated emission processes of the exciton luminescence are studied in quantum wells (QWs) of the Zn1-xCdxSe/ZnSe system. A multiquantum well (MQW) structure shows an exciton lifetime of 150-280 ps and a stimulated emission effect due to exciton-exciton scattering as well as due to electron-hole plasma recombination. A combined-QW structure in which a single quantum well (SQW) is located adjacent to MQWs shows a tunneling process of the excitons from the MQWs through the barriers to the SQW. The stimulated emission takes place in the SQW due to phase space filling effects of the excitons. These observed stimulated emission processes are highly related to the blue-laser-diode operation at both low and room temperatures. 相似文献
16.
S.C. Su Y.M. Lu Z.Z. Zhang B. Yao D.Z. Shen D.X. Zhao 《Applied Surface Science》2008,254(22):7303-7305
In this paper, ZnO/Zn0.9Mg0.1O single quantum well (SQW) structures were fabricated on c-plane sapphire (Al2O3) substrate by plasma-assisted molecular beam epitaxy (P-MBE). The photoluminescence (PL) peak of the SQW shifted from 3.31 to 3.37 eV as the well layer thickness was decreased from 6 to 2 nm. The spectral linewidth increases with temperature due to the scattering of excitons with acoustic and optical phonons. The transition energy of the localized exciton in the ZnO/Mg0.1Zn0.9O SQW with well width of 3 nm was found to be about 3.407 eV at 80 K, consistent with theoretical calculation. The first subband energies in the conduction and valence band were calculated to be 49 and 11 meV, respectively. 相似文献
17.
用脉冲激光沉积(PLD)法在不同温度的Si(111)衬底上成功制备了c轴择优取向的Mg005Zn095O薄膜.通过X射线衍射(XRD)和光致发光谱(PL)研究了衬底温度对Mg005Zn095O薄膜结构和发光特性的影响,探讨了薄膜的结晶质量与发光特性之间的关系.结果表明,在衬底温度为450℃时生长的Mg005Zn095O薄膜具有很好的c轴取向和较强的光致发光峰.室温下分别用激发波长为240,300和325nm的氙灯作为激发光源得到不同样品的PL谱,分析表明紫外发光峰和紫峰来源于自由激子的复合辐射且发光强度与薄膜的结晶质量密切相关,蓝绿发光峰与氧空位有关.此外,探讨了衬底温度影响紫外光致发光峰红移和蓝移的可能机理.
关键词:
005Zn095O薄膜')" href="#">Mg005Zn095O薄膜
PLD
衬底温度
光致发光 相似文献
18.
L.L. Yang Q.X. ZhaoG.Z. Xing D.D. WangT. Wu M. WillanderI. Ivanov J.H. Yang 《Applied Surface Science》2011,257(20):8629-8633
Zn0.94Mg0.06O/ZnO heterostructures have been grown on 2 in. sapphire wafer using metal organic chemical vapor deposition (MOCVD). Photoluminescence (PL) mapping demonstrates that Mg distribution on the entire wafer is very uniform (standard deviation of Mg concentration/mean Mg concentration = 1.38%) with average concentration of ∼6%. The effect of annealing on the Mg diffusion in Zn0.94Mg0.06O/ZnO heterostructures has been investigated in detail by using secondary ion mass spectrometry (SIMS). All the Mg SIMS depth profiles have been fitted by three Gaussian distribution functions. The Mg diffusion coefficient in the as-grown Zn0.94Mg0.06O layer deposited at 700 °C is two orders of magnitude lower than that of annealed samples, which clearly indicates that the deposition temperature of 700 °C is much more beneficial to grow ZnMgO/ZnO heterostructures and quantum wells. 相似文献
19.
Kazuto Koike Gen-you Takada Kazuya Fujimoto Shigehiko Sasa Masataka Inoue Mitsuaki Yano 《Physica E: Low-dimensional Systems and Nanostructures》2006,32(1-2):191
Thermal stability of single-crystalline [ZnO]m[Zn0.7Mg0.3O]n multiple quantum wells (MQWs) grown on a-plane sapphire substrates by plasma-assisted molecular beam epitaxy is reported. X-ray diffraction analysis revealed that these MQWs were grown as designed with a fixed Zn0.7Mg0.3O barrier width of and a series of ZnO well widths of . Cathodoluminescence spectra from these MQWs consisted of two major peaks; one was the emission from the bound excitons in Zn0.7Mg0.3O barrier layers, and the other was that from the confined excitons in ZnO well layers. These structural and optical properties were found to be dramatically changed by the ex situ annealing treatments over 700 °C. These changes were presumably due to the onset of phase separation of the Zn0.7Mg0.3O barrier layers with pronounced Mg diffusion toward the ZnO wells. 相似文献
20.
Cu-doped ZnO films with hexagonal wurtzite structure were deposited on silicon (1 1 1) substrates by radio frequency (RF) sputtering technique. An ultraviolet (UV) peak at ∼380 nm and a blue band centered at ∼430 nm were observed in the room temperature photoluminescent (PL) spectra. The UV emission peak was from the exciton transition. The blue emission band was assigned to the Zn interstitial (Zni) and Zn vacancy (VZn) level transition. A strong blue peak (∼435 nm) was observed in the PL spectra when the αCu (the area ratio of Cu-chips to the Zn target) was 1.5% at 100 W, and ZnO films had c-axis preferred orientation and smaller lattice mismatch. The influence of αCu and the sputtering power on the blue band was investigated. 相似文献