论文部分内容阅读
为了弄清在 GaAs 汽相外延层和衬底交界面之间引起高阻层的深中心的能级,确立了三种测量方法:(1)肖特基势垒电容与时间的关系,(2)肖特基势垒反向电流与温度的关系,(3)高阻区的光电导。在不同温度下测得的电容随时间变化,从中可以发现,在深阱处的电子激活能大约为0.89电子伏。当耗尽层夹在高阻区内时,则肖特基势垒的反向电流比起通常的反向电流约大三个数量级。有关反向电流与温度的关系以及高阻区中光电导光谱的测量结果表明,在价带上面存在着三个深能级,其范围大约为0.3～0.6电子伏。在高阻区,观察到了非本征负光电导。
To clarify the energy level at the deep center between the GaAs vapor-phase epitaxial layer and the substrate interface, three measurement methods were established: (1) Schottky barrier capacitance vs. time, (2 ) Schottky barrier reverse current and temperature relationship, (3) high-resistance photoconductivity. The capacitance measured at different temperatures varies with time, from which it can be seen that the electron activation energy in the deep well is about 0.89 electron volts. When the depletion layer is sandwiched in the high resistance region, the reverse current of the Schottky barrier is about three orders of magnitude larger than the normal reverse current. The relationship between the reverse current and temperature and the photoconductive spectra in the high resistance region show that there are three deep energy levels above the valence band, which range from about 0.3 to 0.6 electron volts. In the high resistance region, extrinsic negative photoconductivity was observed.