The amorphous Si/SiC heterojunction color-sensitive phototransistor

An amorphous Si/SiC heterojunction color-sensitive phototransistor was successfully fabricated by plasma-enhanced chemical vapor deposition. The structure is glass/ITO/a-Si(n⁺-i)/a-SiC(p⁺-i-n⁺)/Al. The device is a bulk barrier transistor with wide-bandgap amorphous SiC emitter and base. The phototransistor revealed a very high optical gain of 40 and a response speed of 10 µs at an input light power of 5 µW and a collector current of 0.12 mA at a voltage of 14 V. The peak response occurs at 610 nm under 1-V bias and changes to 420 and 540 nm under 7- and 13-V biases, respectively.