You see this link :https://books.google.dz/books?id=izaSIlOahJkC&pg=PA329&lpg=PA329&dq=do+anyone+know+a+semiconductor+with+smaller+band+gap+of+insb&source=bl&ots=hbIZLibYas&sig=ACfU3U2ErhOO93QCJCbTRea24nkxswPhyw&hl=en&sa=X&ved=2ahUKEwj3lIWP6bXnAhVKJ1AKHXMsDskQ6AEwAHoECAQQAQ
InSb is a narrow-gap semiconductor with an energy band gap of 0.17 eV at 300 K. Cadmium arsenide(Cd3As2) of Group (II-V ).
N-type intrinsic semiconductor. Very high electron mobility. Used in infrared detectors, photodetectors, dynamic thin-film pressure sensors, and magneto resistors. Recent measurements suggest that 3D Cd3As2 is actually a zero band-gap Dirac semimetal in which electrons behave relativistically as in graphene.