Characterisation of temperature dependent parameters of multi-quantum well (MQW) Ti/Au/n-AlGaAs/n-GaAs/n-AlGaAs Schottky diodes

• Published in: Superlattices and microstructures Vol. 111; pp. 1010 - 1021
• Main Authors: Filali, Walid, Sengouga, Nouredine, Oussalah, Slimane, Mari, Riaz H., Jameel, Dler, Al Saqri, Noor Alhuda, Aziz, Mohsin, Taylor, David, Henini, Mohamed
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.11.2017
• Subjects: Defects; GaAs/AlGaAs Schottky diodes; Inhomogeneous barrier height; MQW; Tunnelling; MQW; Tunnelling; Inhomogeneous barrier height; GaAs/AlGaAs Schottky diodes; Defects
• ISSN: 0749-6036; 1096-3677
• DOI: 10.1016/j.spmi.2017.07.059

Forward and reverse current-voltage (IV) of Ti/Au/n-Al0.33Ga0.67As/n-GaAs/n-Al0.33Ga0.67As multi-quantum well (MQW) Schottky diodes were measured over a range of temperatures from 20 to 400 K by a step of 20 K. The Schottky diodes parameters were then extracted from these characteristics. The Cheung method is used for this purpose, assuming a thermionic conduction mechanism. The extracted ideality factor decrease with increasing temperatures. But their values at low temperatures were found to be unrealistic. In order to explain this uncertainty, three assumptions were explored. Firstly an assumed inhomogeneous barrier height gave better parameters especially the Richardson constant but the ideality factor is still unrealistic at low temperatures. Secondly, by using numerical simulation, it was demonstrated that defects including interface states are not responsible for the apparent unrealistic Schottky diode parameters. The third assumption is the tunnelling mechanism through the barrier in the low temperature range. At these lower temperatures, the tunnelling mechanism was more suitable to explain the extracted parameters values. •AlGaAs/GaAs/AlGaAs multi-quantum well Schottky diodes characterized from 20 to 400 K.•The diode parameters extracted assuming a thermionic conduction mechanism.•The ideality factor was found to be unrealistic especially at low temperatures.•An inhomogeneous barrier height and defects did not explain the unrealistic values at low temperatures.•The tunneling mechanism was more suitable to explain the extracted parameters values.