短周期超晶格AlP／GaP能带结构的转变及其带间的光跃迁

介绍了间接跃迁的半导体ＡｌＰ与ＧａＰ形成的超晶格，由于零折叠效应，实现了能带由间接带隙向直接带隙的转变，从而增加了带间的光跃迁几率，并推导了该几率的表达式。     

SiGe:GaP合金的微观结构和温差电特性

经高温热处理后的 SiGe∶GaP 半导体温差电材料,其微观结构由具有富 Si 相特征变化成为具有富 Ge 相特征,温差电优值也得到了提高。实验还表明,材料晶格热导率的降低与富 Si 相的消失和富 Ge相的出现有关。然而,塞贝克系数和电导率的显著变化却与微观结构中富 Si 相和富 Ge 相的变化基本无关。通过对材料微观结构和温差电特性比较发现,具有富 Ge 相特征的微观结构对应于较大的温差电优值。     

GaP：（N）的背景光谱和发光尖峰

获得高分辨ＧａＰ（Ｎ）光致发光光谱，观察到等电子陷陆束缚激子发光中ＬＯ和ｌｏｃ多声子发射，其强度分布答合泊松分布。将声子伴带区分为直接光跃迁和间接光跃迁，并进行了相应讨论，还观察到局域声子效应－－光谱相似定律和相当显著的背景光谱。     

GaAs、GaP、InP、InGaAsP、AlGaAs、InAlGaAs的化学腐蚀研究

为研制全集成光开关、微片式激光器等，对ＧａＡｓ、ＧａＰ、ＩｎＧａＡｓＰ、ＩｎＡＩＧａＡｓ、ＡｌＧａＡｓ等材料的化学腐蚀进行了实验研究。为了研制ＩｎＡｌＧａＡｓ／ＩｎＡｌＡｓ／ＩｎＡｌＧａＡｓ微片式激光器，开发了Ｈ３ＰＯ４／Ｈ２Ｏ２／Ｈ２Ｏ薄层腐蚀液和ＨＣｌ／Ｈ２Ｏ选择性腐蚀液；为了研制ＩｎＧａＡｓＰ／ＩｎＰ／ＩｎＧａＡｓＰＴｂａｒ型光波导，开发了ＨＣｌ／Ｈ３ＰＯ４／Ｈ２Ｏ２薄层腐蚀液和ＨＣｌ／Ｈ２Ｏ２选择性腐蚀液；为了研制ＧａＰ、ＩｎＧａＰ光波导，开发了ＨＣｌ／ＨＮＯ３／Ｈ２Ｏ薄层腐蚀液。它们都具有稳定、重复性好、速率可控、腐蚀后表面形貌好等特点。除此之外，蚀刻成的ＧａＰ光波导侧壁平滑无波纹起伏。此种结果尚未见报导。     

GaP/GaNP Heterojunctions for Efficient Solar‐Driven Water Oxidation

The growth and characterization of an n‐GaP/i‐GaNP/p⁺‐GaP thin film heterojunction synthesized using a gas‐source molecular beam epitaxy (MBE) method, and its application for efficient solar‐driven water oxidation is reported. The TiO₂/Ni passivated n‐GaP/i‐GaNP/p⁺‐GaP thin film heterojunction provides much higher photoanodic performance in 1 m KOH solution than the TiO₂/Ni‐coated n‐GaP substrate, leading to much lower onset potential and much higher photocurrent. There is a significant photoanodic potential shift of 764 mV at a photocurrent of 0.34 mA cm^?2, leading to an onset potential of ≈0.4 V versus reversible hydrogen electrode (RHE) at 0.34 mA cm^?2 for the heterojunction. The photocurrent at the water oxidation potential (1.23 V vs RHE) is 1.46 and 7.26 mA cm^?2 for the coated n‐GaP and n‐GaP/i‐GaNP/p⁺‐GaP photoanodes, respectively. The passivated heterojunction offers a maximum applied bias photon‐to‐current efficiency (ABPE) of 1.9% while the ABPE of the coated n‐GaP sample is almost zero. Furthermore, the coated n‐GaP/i‐GaNP/p⁺‐GaP heterojunction photoanode provides a broad absorption spectrum up to ≈620 nm with incident photon‐to‐current efficiencies (IPCEs) of over 40% from ≈400 to ≈560 nm. The high low‐bias performance and broad absorption of the wide‐bandgap GaP/GaNP heterojunctions render them as a promising photoanode material for tandem photoelectrochemical (PEC) cells to carry out overall solar water splitting.     

GaP高能重离子辐照损伤及退火的正电子湮没研究

用正电子湮没寿命技术研究２．４＊１０＾１５／ｃｍ＾２和２．２＊１０＾１６／ｃｍ＾２ ８５ＭｅＶ＾１９Ｆ离子辐照ＧａＰ的辐照损伤及其退火效应。结果表明，高低两种注量辐照在ＧａＰ中产生浓度较高的单空位。在３００－１０２３Ｋ温度范围内测量了正电子湮没寿命温度的变化。低注量辐照品在退火过程中有双空位的形成；而高注量辐照样品中观察到比双空位更复杂的缺陷形式，其完全被退火的温度比低剂量辐照的高２５０Ｋ。     

新型红光LED中ITO的特性研究

用真空电子束蒸镀的方法制备半导体发光二极管LED 所用的ITO(indium tin oxide)膜。利用TLM(transmission line model)研究ITO与GaP接触特性。在氮气环境,435℃条件下,快速热退火40s能获得最小的接触电阻4.3×10-3Ωcm2。Hall测试和俄偈电子能谱表明,影响接触电阻的主要原因是ITO载流子浓度的改变和In,Ga,O的扩散。另外,制作了以300nm ITO为窗口层的新型AlGaInP红光LED并研究其可靠性。发现ITO的退化导致了LED的电压持续升高。而ITO与GaP热膨胀系数的不同导致了LED的最终失效。     

In-situ monitoring of InP(100) and GaP(100) interfaces and characterization with RDS at 20 K

MOVPE-preparation of highly ordered InP(100) and GaP(100) surfaces was monitored with in-situ reflectance difference spectroscopy (RDS). Specific ordered P-terminated and ordered cation-terminated surface reconstructions were identified with specific structured RD spectra with the highest peaks. After contamination-free transfer of the samples to UHV, RDS measurements were performed also at 20 K. The experimental RD spectrum for the In-terminated, (2×4) reconstructed InP(100) surface shows a remarkable similarity to a recently published theoretical spectrum, whereas there is only moderate similarity between the experimental RD spectrum for the (2×4) reconstructed Ga-terminated GaP(100) surface and a recently proposed theoretical spectrum.     

Low temperature growth of AIGaP and GaP on si substrates by atomic layer epitaxy

AIGaP and GaP films were deposited on the (100) Si substrates by atomic layer epitaxy (ALE) in the temperature range between 450 and 600°C. Under optimum growth conditions, the growth of GaP and AIGaP was observed to proceed in a two-dimensional (2-D) fashion in the initial growth stages. These ALE-grown films have better surface morphology when compared with the corresponding MOCVD-grown films. With an AIGaP buffer layer grown on Si, the subsequent growth of GaAs on the AlGaP-coated Si substrates tends to proceed as 2-D growth. This avoids island growth and the two-step growth process currently used.     

Real-time optical monitoring of epitaxial growth: Pulsed chemical beam epitaxy of GaP and InP homoepitaxy and heteroepitaxy on Si

We present a study of the real-time monitoring of the homoepitaxial growth of GaP, InP, and the growth of InP/GaP and GaP/Si(001) heterostructures, combining single wavelength p-polarized reflectance (PRS), reflectance-difference spectroscopy (RDS), and laser light scattering (LLS) during pulsed chemical beam epitaxy with tertiarybutylphosphine, triethylgallium, and trimethylindium sources. The growth rate and the bulk optical properties are revealed by PRS with submonolayer resolution over 1000A of film growth. The surface topography is monitored by LLS providing additional information on the evolution of the surface roughness as well as the nucleation/growth mechanism. The optical surface anisotropy, which is related to surface reconstruction and/or surface morphology, is monitored by RDS and compared with the results of PRS and LLS. The results are discussed with respect to the deposition kinetics, in particular as a function of the V:III flux ratio. The pulsed supply of chemical precursors causes a periodic alteration of the surface composition, which is observed as correlated periodic changes in the RD and PR signals, confirming the high sensitivity of both methods to surface chemistry.