Semiconducting hydrides

Using first-principles density functional calculations with AlH ₃, KMgH₃, LiMgH₃, NaBeH₃, NaMgH ₃, and RbMgH₃ as model systems we have analyzed the band structure of hydrides. It is shown that hydrides can possess the features of semiconductors with n- and/or p-type electrical conductivity. We have found that carrier effective masses of some hydrides are almost the same as those of commonly known semiconductors. The present study suggests that the Mg impurities substituting Al form a shallow acceptor level in the band gap of AlH ₃, which can provide holes and cause p-type electrical conductivity. From studies of optical properties we have found that even if Mg impurities of about 1.3×10²¹ cm^-3 concentration substitute the Al site, AlH₃ can still be transparent in the visible spectra. This result opens up the door for the application of hydrides in the future generation of optoelectronic devices.