低温大注入多晶硅发射极硅双极晶体管电流增益的定量模拟

已有的理论和实验都已证明，多晶硅发射极硅双极晶体管适合于低温工作。但至今为止，其完整的大注入时电流增益的理论分析还不成熟，特别是进行定量的计算；本文定量地模拟了低温７７Ｋ和常温３００Ｋ下多晶硅发射极硅双极晶体管电流增益与集电极电流密度的关系，并且分析了低温和常温下决定该晶体管电流增益大注入效应的主要物理效应，为低温多晶硅发射极硅双极晶体管的设计提供了有益的理论基础。

PESC太阳电池双层减反射膜的研究

钝化发射极硅太阳电池（简称为PESC）^[1]，采用浅结密栅结构，以改革蓝光响应，提高转换效率。同时要求硅太阳电池的减反射在短波范围有较好的透射性能。本文对MgF2-Zn双层减反射进行了研究，将其用于PESC中，有效地提高了电池的短波光谱响应。在AM1．5mw/cm^2光照下得到太阳电池短路电流增益高达1．47，平均反射率在3％左右。

Flux-adjusted phase transformation from Ca_2SiO_4 to Ca_3Si_2O_7 with Eu^(2+) activator for white light emitting diodes

Eu2+ -activated reddish-orange-emitting Ca3Si2O7 phosphors were synthesized with the addition of NH4Cl flux.When the phosphors were synthesized in a nominal composition of (Ca0.99Eu0.01)3Si2O7 without flux addition,a Ca3Si2O7 phase responsible for reddish-orange emission was identified to coexist with an intermediate phase of a-Ca2SiO4 for green emission.With the addition of NH4Cl flux,a-Ca2SiO4 was suppressed while the pure phase Ca3Si2O7 was obtained as the flux content was 3 wt%.Through varying the amount of flux,the emission color of samples can be tuned from green to reddish-orange,corresponding to the phase transformation from a-Ca2SiO4 to Ca3Si2O7.Through optimizing the doping concentration of Eu2+ ,the optimized photoluminescence (PL) properties for reddish-orange emission can be achieved,which makes this kind of phosphor prospective in the applications of the phosphor-converted white light emitting diodes (PC-WLEDs).

半导体器件

Y99-61799-365 0007491场发射阵列的技术与材料=Field emitter arrays tech-nologies and materials[会,英]/Kleps,I.& Banoiu,G.//Proceedings of 1998 International SemiconductorConference,Vol.2.—365～368(UG)利用不同的微加工技术已加工出具有各种图形特点的硅发射阵列。其发射极的几何形状能利用变化其技术参数(腐蚀率,选择性和表面形貌)进行修正。为改进其场发射特性,还能用各种材料对硅发射极进行包敷。