A transistor is a miniature semiconductor that regulates or controls the flow of current or voltage while also amplifying and generating electrical signals and acting as a switch/gate for them.
Transistor cannot be used as a rectifier.
The emitter-base segment or the collector-base segment of a transistor must be used as a rectifier.
The base of a transistor is thinner than the emitter and collector and is lightly doped, so neither segment functions as a proper rectifier.