The electrical characterization of ZnO/GaAs heterojunction diode

• We have fabricated Al/ZnO/p-GaAs heterostructure diode by sol–gel method.
• The current–voltage characteristic of Al/ZnO/p-GaAs shows diode-like behavior.
• AFM images indicate that the ZnO films are formed from the nano-fiber particles.
• It is evaluated that electrical performance of Al/ZnO/p-GaAs can be controlled by ZnO.

The electrical characteristics of sol–gel synthesized n-ZnO/p-GaAs heterojunction were reported. The values of barrier height and ideality factor for n-ZnO/p-GaAs heterojunction diode were determined to be 0.61 eV and 1.83, respectively. The I–V characteristics of the heterojunction diode exhibit a non-ideal behavior. The ideality factor which is greater than unity was attributed to the series resistance, interface states and interfacial layer. The modified Norde׳s function combined with conventional forward I–V method was used to obtain the parameters including the series resistance and barrier height (BH). The capacitance–voltage (C–V) measurements were performed in the range of 100 kHz to 1 MHz. The interface distribution profile (Dit) as a function of bias voltage was extracted from the C–V and Gadj–V characteristics. The interface state density of n-ZnO/p-GaAs diode is of the order of 1013 eV−1 cm−2. Also, the I–V characteristics of n-ZnO/p-GaAs heterojunction diode were investigated in the temperature range of 293–393 K.

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