Gas source MBE growth of TlInGaP and TlInGaAs as new materials for long-wavelength applications

摘要

The gas source MBE grown layers exhibited (2/spl times/4) surface reconstruction. X-ray diffraction measurements showed the successful growth of TlInP, TlGaP, TlInGaP and TlInAs. No phase separation was observed in TlInP and TlInGaP grown on InP substrates and TlInAs on InAs, while phase separation was observed in TlGaP grown on GaAs. PL emission was observed for TllnP and TlInGaP grown on InP. The layers showed n-type conduction with an electron concentration of 6.3/spl times/10/sup 15/ (3.9/spl times/10/sup 15/) cm/sup -3/ and an electron mobility of 2,500 (22,000) cm/sup 2//V.s at room temperature (77 K) for TlInP with a Tl composition of 5%. Photocurrent versus wavelength measurements showed a decrease of band gap energy by the addition of Tl and that its temperature variation is smaller than that of InAs, indicating the possibility of temperature independent band gap energy in these alloy semiconductors.