Positron annihilation in silicon in thermal equilibrium at high temperature
Positron annihilation in silicon in thermal equilibrium at high temperature
复制标题
高温热平衡硅中的正电子湮灭
DOI：
10.1088/0953-8984/12/5/318
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发表时间：
2000
期刊：
影响因子：
--
通讯作者：
S. Tanigawa
中科院分区：
文献类型：
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作者：
A. Uedono;M. Watanabe;S. Takasu;T. Sabato;S. Tanigawa
用单能正电子束研究了高温热平衡下正电子在硅中的湮灭特性。在298-1618 K温度范围内，测定了正电子在表面S_s湮灭的多普勒展宽谱的线形参数和正电子D ~+的扩散系数。在298-1373 K，由于正电子从表面态热脱附并由此形成正电子素（Ps），Ss值随温度升高而增加。然而，在1473 K以上，它开始下降。Ss值的降低归因于由于表面熔融而抑制Ps形成。随着温度的升高，D +的值由正电子与声学和光学声子的散射而减小，并且在1073 K以上，它几乎是恒定的; D +的下限被确定为0.48 cm 2 s-1。本文还从多普勒展宽谱的分析出发，讨论了高温下体硅中正电子的行为。
Annihilation characteristics of positrons in Si in thermal equilibrium at high temperature were studied using a monoenergetic positron beam. The line-shape parameter of the Doppler broadening spectrum for the annihilation of positrons at the surface Ss and the diffusion coefficient of positrons D + were determined in the temperature range 298-1618 K. At 298-1373 K, because of the thermal desorption of positrons from the surface state and a resultant formation of positronium (Ps), the value of Ss increased with increasing temperature. However, it started to decrease above 1473 K. The decrease in the value of Ss was attributed to the suppression of the Ps formation due to the surface melting. With increasing temperature, the value of D + was decreased by the scattering of positrons with acoustic and optical phonons, and above 1073 K, it was almost constant; the lower limit of D + was determined as 0.48 cm2 s-1 . From the analysis of Doppler broadening spectra, the behaviour of positrons in bulk Si at high temperature are also discussed.