A semiconductor device is connected in series circuit with a battery and resistance. A current is found to pass through the circuit. If the polarity of the battery is reversed, the current drops at almost zero. The device may be

A p-n Junction

A PN junction is a device in which current flows through the junction when it is forward biased whereas on reversing the polarity of the battery the PN junction is reverse biased. As a result of which its resistance becomes high and current through the junction drops to almost zero.

Current through the intrinsic as well as extrinsic semiconductor does not depend on the polarity of the battery.