Luminescence Absorption And Pressure Studies Of Nitrogen Doped And Nitrogen Free Gallium Arsenide Phosphide And Indium Gallium Phosphide

Author : Eric Albert Stinaff
Publisher :
ISBN 13 :
Total Pages : 318 pages
Book Rating : 4.:/5 (517 download)

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Download or read book Optical Properties of Nitrogen Doped Gallium Arsenide Under Pressure written by Eric Albert Stinaff and published by . This book was released on 2002 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present new insights into the problem of the isoelectronic nitrogen (N) impurity in gallium arsenide (GaAs). By performing photoluminescence (PL), photoluminescence excitation (PLE), transmission, and time decay measurements through a broad range of pressures, we were able to positively identify and track previously unseen states arising from the N impurity. The first observation we make is of a dramatic increase in luminescence as N forms an isolated state within the gap around 22kbar. We attribute this effect to N acting as a nonradiative trapping center while still resonant with the conduction band states. We also note the appearance, above 22kbar, of a broad band-to-acceptor like emission below the band edge, which we associate with a band to N acceptor transition. The next major observation we report is of the excited state of the N[Subscript x] exciton. We find this state to be clearly identifiable for the pressure range [Difference symbol]25kbar to [Difference symbol]30kbar, and is weak in PL, but shows enormous absorption signals in PLE and transmission. The spacing of this level from N[Subscript x]-B is in good agreement with the established theory of shallow acceptor levels. We then move on to the identification of a second bound state associated with N. This state, designated N[Subscript Gamma symbol], was previously reported for the GaP system and the GaAs[Subscript l-x]P[Subscript x] alloy, but has not, until now, been positively identified in GaAs. We find the state to be degenerate with the shallow donor level for pressures up to [Difference symbol]30kbar. The emission from this state is found to possess unique N characteristics and is seen to move in pressure with both shallow and deep like properties. We conclude with a discussion of the process of lasing in N doped GaAs. We present data consistent with previous studies of the lasing process in GaAs. However, we find an intriguing trend with pressure as we approach the [Gamma]-X crossover. The lasing gain begins to shift in a manner similar to N[Subscript Gamma]. In fact, N[Subscript Gamma] appears to act as an upper bound on the laser emission. We believe this to be preliminary evidence of the influence of N on the lasing mechanism.