The mechanism for the 1.54 mum luminescence of erbiumdoped porous silicon and the method of attaining a high efficiency.

在1997年的研究中，选择了Er、Yb、Nd和Ho作为稀土元素，并将它们掺入多孔硅(PS)和晶体硅(c-Si)中，由Er掺杂多孔硅(PS)产生的4f电子跃迁产生的1.54 nm的发光，原来的宽度约为10 nm。在本研究期间，我们引入了掺Er后在-1000ﾟC下进行的氢等离子体退火，获得了由尖峰组成的光谱，这些峰的半峰全宽小于1 nm。我们解释说，经过氢等离子体处理后，氧化硅和非晶硅区被刻蚀掉了，剩下的掺Er硅纳米晶出现了尖锐的峰，这些尖锐的发光峰存在着一个小的热猝灭。这是由于硅纳米晶体的带隙增加：(在MRS 1997秋季会议上提出，并提交给J.Apple.Phys.)我们研究了Yb掺杂PS的Yb-1.0um发光作为主机PS处理工艺的函数。PS的预氧化使Yb的发光强度增加了一个数量级。对PS和Yb发光衰减时间的测量表明，PS的悬挂键被氧钝化后，非辐射复合中心减少，导致从PS到Yb的能量转移效率增加。我们测量了掺钕多孔硅的衰减时间，得到了0.93微米和1.06微米两个发光峰的衰减时间为200-300微秒。在与阿姆斯特丹FOM研究所的A.Polman博士的合作中，将Ho离子注入到c-Si中，首次观察到了4f电子跃迁引起的-1.2微米的发光。

In the 1997 research year, Er, Yb, Nd as well as Ho were chosen as rare earth elements and were incorporated into porous silicon (PS) as well as crystalline silicon (c-Si) hosts.The 1.54 mum luminescence due to the 4f electron transition from Er-dope PS showed formerly a width of about 10nm. In this research period, we introduced a hydrogen plasma annealing at -1000ﾟC after Er incorporation and obtained spectra composed of sharp peaks whose full-width-at-half-maximu (FWHM) is less than 1nm. We explained that silicon oxide and amorphous silicon regions were etched off by the hydrogen plasma treatment and that the remained Er-doped silicon nanocrystals showed sharp peaks.These sharp luminescence peaks exibited a small thermal quenching. This was due to the increased bandgap of silicon nanocrystals : (Presented in the MRS 1997 Fall Meeting, and submitted to J.Apple.Phys.)We studied the Yb - 1.0 mum luminescenece from Yb doped PS as a function of host PS treatment processes. Pre-oxidation of PS resulted in the one-order increase in the Yb luminescence intensty. Measurements of the decay times of PS and Yb luminescence showed that the passivation of the dangling bonds of PS with oxygen reduced the nonradaitive recombination centers, which led to an increse in the enrgy transfer efficiency from PS to Yb. (presented in J.Appl.Phys.)We measured the decay time of Nd doped PS,and obtained the decay times of 200-300 mus for the 0.93 mum and 1.06 mum luminescence peaks. In colaboration with Dr.A.Polman of FOM institue in Amsterdam, Ho ions were inplanted into c-Si, and the luminescence at - 1.2 mum due to the 4f-electron transition was observed for the first time.