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The ternary semiconductor Ga_(0.5)In_(0.5)Pmay be used in optoelectronics andmicrowave devices to overcome the problemssuch as the formations of DX centers andoxidation of Al that occurred frequently inAIGaAs.It can also be used as active regionsin GalnP/AlGalnP visible double 相似文献
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溴化物熔盐可能成为制备、精炼和再生难熔金属以及研究熔盐本性的熔体。本文就溴化物熔盐中钛的电化学行为进行了研究。文中曾用溴化法、阳极溶解法和 TiBr_2加入法制得了含钛达10%左右的溴化物熔体。由此建立了如下的电池:Ti|TiBr_2-MBr| |AgBr(N=0.1)-MBr|Ag (Ⅰ)其中参考电极 Ag|Ag~ ,MBr 系通过石棉隔膜与熔体接触,证明无扩散电势存在;而以这种参考电极测得的 AgBr-KBr 和 AgBr-NaBr 的热力学性质表明,该二体系均为规则溶液,它们分别呈不大的负偏差和正偏差。电池(Ⅰ)的电动势测量结果表明,当 N_(TiBr_2)<2.66×10~(-2)时上述三种方法制得的熔体中主要为 Ti~( ),并且它们的电动势十分符合。据此,已算得 TiBr_2-KBr 和 TiBr_2-NaBr 熔体中 TiBr_2的活度系数分别为0.1585和1.585;而 KBr 熔体中 E_(Ti/Ti~( ))~0、E_(Ti/Ti~( ))~0和 E_(Ti~( )/Ti~( ))~0则分别为1.458、1.438和1.427伏。根据活度系数值,讨论了溴化物熔体的本性和说明了组元活度系数和熔盐阳离子半径的关系。最后用化学分析法讨论了钛含量达10%时溴化物熔体中 Ti~0-Ti~( )-Ti~( )的平衡,验证了 Ti%<1%时,熔盐中 Ti~( )含量仅占5%左右,这与电动势算得的结果是一致的。 相似文献
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本文报导用石墨舟液相外延纯度砷化镓材料的电学性质。在氢中含氧量为0.12×10~(-6)的条件下,获得的较好生长层的电学参数为μ_(77)~K=9.41×10~4~1.22×10~5厘米~2/伏·秒,n_(77)K=3.77×10~(13)~4.53×10~(14)厘米~(-3)。另外,研究了系统漏气及氢中含氧量对浅施主浓度N_D、熔融KOH腐蚀坑密度和生长层表面氧化膜的影响以及这些参数间的相互关系。 根据生长层的电学性质,计算了室温迁移率的计算值与实测值之差Δμ300K。发现,后者随N_D增加而降低,恰与前一文报导的用石英舟液相外延的情况相反。由此推测,在本文实验条件下,迁移率刽子手的本性也与前文有所不同,而以碳或碳化物较为可能。 相似文献
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The GalnAsSb quaternary alloys for 2~4 μm long wavelength optoelectronics have been prepared byMOCVD.The growth of buffer layers and the employment of GaSb/GaAs and GaSb/GaSb hybridsubstrates are mentioned,which effectively improve the properties of GalnAsSb epilayers.In order to controlthe epitaxial growth of GaSb and GalnAsSb,emphasis is given on the deposition rates,growth temperaturesand the relationship between growth conditions and the distribution coefficients of In and Sb.The experimen-tal solid compositions in this work are predicted by the thermodynamic calculations.Whether the growth ofGalnAsSb epilayers is controlled by chemical reactions or by mass diffusions depends on growth temperatures.This argument is verified by kinetic considerations.The FWHMs of the DCXD (double crystal X-raydiffraction)spectra of GalnAsSb epilayers grown on GaSb/GaSb and GaSb/GaAs hybrid substrates areabout 200~300 arcsec and 800 arcsec respectively.The unintentionally doped GalnAsSb epilayers have themobilities of μp=100~240 cm~2/V·s at 300 K.The corresponding wavelength ofMOCVD GaInAsSb alloysis calculated from EPMA(electronic probe microanalysis)data and determined by FTIR(Fourier transformedinfrared spectroscopy)measurement. 相似文献
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本文用GSMBE技术生长纯度GaAs和δ-掺杂GaAs/Al_xGa_(1-x)As结构二维电子气材料并对其电学性能进行了研究。对于纯度GaAs的GSMBE生长和研究,在低掺Si时,载流子浓度为2×10~(14)cm~(-3),77K时的迁移率可达84,000cm~2/V.s。对于用GSMBE技术生长的δ-掺杂GaAs/Al_xGa_(1-x)As二维电子气材料,在优化了材料结构和生长工艺后,得到了液氮温度和6K迁移率分别为173,583cm~2/V.5和7.67×10~5cm~2/V.s的高质量GaAs/Al_xGa_(1-x)As二维电子气材料。 相似文献
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本文研究了InGaP/GaAs异质结构的气态源分子束外延(GSMBE)生长,所得样品晶格失配率△α/α<8.95×10 ̄(-5),本底载流子浓度为10 ̄(15)cm ̄(-3)数量级,掺硅n型样品的载流子浓度控制范围可达2×10 ̄(15)~4×10 ̄(18)cm ̄(-3)。研究了P_2和As_2气氛的切换条件对InGaP/GaAs异质结构界面特性的影响,并成功地生长了InGaP/GaAs异质结双极晶体管(HBT)结构材料,用此材料在国内首次制成的HBT器件fr=25GHz,f_(max)=46GHz,电流增益β=40,最高可达β=150。 相似文献
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GaSb epilayers were grown on GaAs and/or GaSb substrates by MOCVD respectively.The influenceof growth conditions on the properties of the epilayers was studied in order to improve the growth pro-cesses.The growth mechanism of MOCVD GaSb was investigated.An equation derived for chemical reac-tion controlled growth rate of MOCVD GaSb was verified by the experiments.The typical FWHM of doub-le crystal X-ray diffraction(DCXD)spectra of GaSb epilayers on GaSb and/or GaAs substrates are 20arcsec and 150 arcsec,respectively.The 300 K hole concentration of p=1.2×10~(16)cm~(-3) with Hall mobilityof 898 cm~2/V·s is obtained. 相似文献
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