الملخص الإنجليزي
GaAs p-i-n diode incorporating a double barrier single quantum well structure in the intrinsic region has been utilized in many fields of optoelectronic devices. It is found that dark current transport mechanisms are notably depending on both temperature and voltage. Thus in this study the dark (I-V) characteristics of DBQW p-i-n GaAs structure are investigated over a wide temperature range (20K-300K). The electrical parameters as the ideality factor (n), the saturation current (1,) and the series
resistance (R) are obtained from the dark forward (I-V) measurements. The values of R, which are extracted from Werner method increase as the temperature increases due to the effect of external connection. While analysis of the variation of n with temperature indicates that the dark current is dominated by the bulk recombination above 200K and by the tunneling enhanced recombination below 200K. The High values of n(n>2) are attributed to the existence of defects and localized trap states in the space charge region which assumed to distribute uniformly in (SCR). In the reverse bias regime where the saturation current strongly depends on the applied voltage, the dark current is limited by Poole-Frenkel emission at high temperatures. Whereas at low temperatures, the tunneling current controls the dark current of both regimes. In addition, below 120K the negative differential resistance (NDR) appears owing to the resonant tunneling of charge carriers through quasi-bound states of the QW which speculated to have significant influence on the dark current by their net charges.
