Temperature and voltage dependent current-transport mechanisms in GaAs/AlGaAs single-quantum-well lasers

Abstract

The quantum-well (QW) lasers are the most important optoelectronic devices in many application fields and the current-transport mechanisms (CTMs) are strongly depend on temperature and voltage. Therefore, we have examined the samples in the temperature range of 80–360 K. The electrical parameters such as saturation current ( I o), zero-bias barrier height ( Φ Bo), ideality factor ( n) and series resistance ( R s), were obtained from the forward bias I– V data. The n and Φ Bo values change from 3.49 and 1.313 eV (at 80 K) to 1.73 and 0.492 eV (at 360 K), respectively. These values of n indicate that the thermionic field emission (TFE) mechanism is dominated the others, particularly at low temperature (80–170 K). High values of n were attributed to image force lowering of the barrier height, tunneling current at low temperature, generation-recombination current within the space charge region and the existence of interface states at metal/semiconductor interface. The Φ Bo values do not have to be absolutely correct, especially when there are more CTMs present in a given temperature interval. Also, n and R s were found to be extremely dependent on the contributions of particular CTMs to the total current; the ratio of which to the TE theory increases with the increasing temperature. The Φ Bo and activation energy ( E a) values decrease with the linearly increasing temperature and voltage. In addition, double-logarithmic plots of the forward bias I– V characteristics have shown two distinct linear regions in the whole temperature range. SCLC mechanism may be dominated CTMs especially at high temperature regime namely regime II.