半导体的电子生伏打效应的理论

一.引言 以高速电子注射到具有阻挡层的半导体光电池上,其效果和光線相类似,使光电池的两极间产生电动势。这种效应可称为电子生伏打效应。这效应首先在1937年由Becker和Kruppke研究过,以后Ehrenberg,蓝继熹和West做了更有系统的测量。他们的测量结果表明,当电子注的能量逐渐增加时,光电池的电动势(以下简称次级电动势)最初很快地增加,达到一个极大值后又逐渐减少。相当于最大次级电动势

THE THEORY OF ELECTRON VOLTAIC EFFECT IN SEMICONDUCTOR

The electron voltaic effect of semiconductor was first studied by Becker and Kruppke (see ref. 1) and later by Ehrenberg, Lang and West (see ref. 2 & 3). They found that the e.m.f. developed on the photo element under the bombardment of electron beam increases at first rapidly with accelerating voltage, reaches a maximum and then decreases. The accelerating voltage corresponding to the maximum e.m.f. developed on the cell was found to be various from cell to cell. In this paper a detailed theory of electron voltaic effect was developed under the assumption that the primary current of the electron beam is so small that a linear appoximation may be used. The Thomson-Whiddington law is used for getting the energy dissipation of the electron beam in semiconductor. The results of the present theory show that the e.m.f. developed on the cell appears a maximum, when the depth for which the incident electrons penetrate into the semiconductor is of the same order of the diffusion length of the excited electrons, rather than the thickness of the barrier layer. The numerical calculation is carried out for some typical examples and the results are discussed and compared with the experimental data.