About the 8th Biennial Workshop on OMVPE: Technical Program, Tuesday Morning Sessions (April 15)

The following papers will be presented at the 8th Biennial Workshop on OMVPE, on Tuesday morning, April 15th, 1997. The calendar of events describes the entire technical program.

SESSION IV: QUANTUM STRUCTURES I

OMVPE Growth of GaInAsSb/AlGaAsSb for Quantum-Well Diode Lasers: C.A. Wang and H.K. Choi, Lincoln Laboratory, Massachusetts Institute of Technology, Lexington, MA 02173-9108

Antimonide-based semiconductors are important materials for lasers emitting in the range 2 to 5 mm for trace gas sensing, molecular spectroscopy, and target illumination. In this paper, we will report GaInAsSb/AlGaAsSb multiple-quantum-well structures which have been grown for the first time by OMVPE. GaInAsSb quantum wells were grown with triethylgallium (TEGa), trimethylindium, tertiarybutylarsine (TBAs), and trimethylantimony (TMSb), while AlGaAsSb barrier layers were grown with tritertiarybutylaluminum, TEGa, TBAs, and TMSb. All layers were grown nominally lattice-matched to GaSb substrates at 575°C with V/III = 1.15 or 2.2 for GaInAsSb or AlGaAsSb, respectively. The growth rate of the quantum wells was typically 0.7 nm/s while that of the barrier layers was 0.4 nm/s. Because of a limited number of sources, growth was interrupted between successive layers. For optimum interruption times and purging sequences, sharp satellite peaks were observed in double-crystal x-ray diffraction rocking curves. Room-temperature photoluminescence emission was observed at ~2mm. We will discuss the effects of various growth interruption times on the optical and structural quality of these GaInAsSb/AlGaAsSb multiple-quantum-well structures. We will also report the growth and device performance of the first GaInAsSb/AlGaAsSb quantumwell diode lasers grown by OMVPE. The laser structure consists of n- and p-Al0.6Ga0.4As0.05Sb0.95 cladding layers, Al0.3Ga0.7As0.02Sb0.98 confining layers, and four 15-nm-thick Ga0.87In 0.13As0.12Sb0.88 quantum wells with 20-nm-thick A10..3Ga0.7As0.02Sb0.98 barrier layers, all lattice-matched to a GaSb substrate. These lasers, emitting at 2.1 mm, have exhibited pulsed threshold current densities as low as 1.2 kA/cm2.

8:40 am

The Growth of InAs/InAsP Strained-Layer Superlattices for use in Infrared Emitters: R.M. Biefeld, A.A. Allerman, S.R. Kurtz, and J.H. Burkhart, Sandia National Laboratories, Albuquerque, NM 87185-0601

We are developing mid-infrared (3-6 mm) lasers and LED's for use in chemical sensor systems. We have demonstrated an electrically injected, 3.9 mm laser with a strained InAsSb/InAs active region which operated up to 210K. To improve the operating characteristics of our lasers we are exploring the growth of InAsSb/InAsP SLSs lattice matched to InAs as active regions. The splitting of the light and heavy hole states should reduce the non-radiative Auger recombination in these structures and improve the operating characteristics of the lasers. These SLSs were grown at 500°C and 200 torr in a horizontal quartz reactor using TMIn, TESb, AsH3, and PH3. By changing the layer thickness and composition we have prepared structures with room temperature photoluminescence wavelengths ranging from 3.2 to 4.8 mm. We have grown an optically pumped, single heterostructure SLS/ALAsSb laser that emitted at 3.6 mm with a maximum operating temperature of 220 K. We have also made LEDs utilizing a GaAsSb/InAs semimetal injection scheme. The LEDs operated at 4.2 mm and 300K. *This work was supported by the US DOE under Contract DE-AC04-94AL85000.

9:00 am

The Growth of InAsSb-Based Mid-Infrared Lasers and Light Emitting Diodes by Organometallic Vapor Deposition: A.A. Allerman, R.M. Biefeld, K.C. Baucom, S.R. Kurtz, and J.H. Burkhart, Sandia National Laboratories, Albuquerque, NM 87185-0601

Chemical sensor systems are being developed which require emitters in the mid-infrared (36mm) range. The active regions are As-rich InAsSb-InAs multi-quantum well heterostructures in which the optical emission can be tuned between 4 to 6 mm. Optical confinement is obtained using AlAs1-xSbx epitaxial layers grown using trimethylamine alane or ethyldimethylamine alane, triethylantimony and arsine. We will present the growth conditions and a regrowth procedure used to create injection lasers and multistage LED's in a horizontal OMVPE reactor. Gain guided injection lasers have operated to 210K in pulsed operation with an emission wavelength of 3.83.9mm. Laser pulse duration has been extended from l0msec to lmsec by doping the GaAsSb-AlAsSb heterojunctions with diethylzinc. Room temperature emission from LED structures spans the 4 to 5 mm range with lmW output power. The addition of an AlAs1-xSbx electron confinement layer in LED structures improves output power by a factor of 4. The performance of devices employing a semi-metal p-GaAsSb/n-InAs heterojunction as a source for electron injection and conventional p-n junction injection will be presented. This work was supported by the US DOE under Contract DEAC0494AL85000.

9:20 am

MOVPE of ZnMgSSe Heterostructures for Optically Pumped Blue-Green Lasers: H. Kalisch, H. Hamadeh, J. Mueller, G.P. Yablonskii* , A.L. Gurskii* , M. Heuken, Institut fur Halbleitertechnik, RWTH Aachen, Templergraben 55, D-52056 Aachen, Germany, * Institute of Physics, Belarus Academy of Science, F. Skaryna pr. 68, 220072 Minsk, Belarus

We report on the growth of ZnMgSSe/ZnSSe/ZnSe hetero structures in a low pressure MOVPE system at a total pressure of 400 hPa and a growth temperature of 330C. Optimization of the growth process finally led to a novel precursor combination. These precursors were dimethylzinc (triethylamine adduct), ditertiarybutylselenium, ditertiarybutylsulphur and bismethylcyclopentadienylmagnesium. This combination allows the reproducible adjustment of the sulphur and magnesium contents in a wide range maintaining high crystal homogeneity and almost lattice matched growth. Separate confinement heterostructure lasers with ZnMgSSe cladding and ZnSSe guiding layers were deposited on GaAs substrates. X-ray diffraction (reciprocal space mapping), photoluminescence (PL) at 14 - 300 K, PL-excitation and optical pumping experiments were performed. The quantum wells show a high luminescence efficiency up to room temperature. Optical pumping experiments were carried out at various temperatures (77 K 300 K) and excitation densities using a nitrogen laser. The lasing threshold could be determined to be less than 20 kW/cm2 at 77 K, and even room temperature lasing was observed at an excitation density below 200 kW/cm2. A further reduction of lasing thresholds is expected by using a cladding material with a higher bandgap (higher sulphur and magnesium contents) and by optimizing the active region.

9:40 am

ZnS/Si/ZnS Quantum Well Structures for Light Emitting Devices: Eric Bretschneider*, Clint McCreary+, Albert Davydov+, Timothy J. Anderson+, and H. Paul Maruska++, * Emcore Corporation, 394 Elizabeth Ave., Somerset, NJ 08873, + Chemical Engineering Department, University of Florida, Gainesville, FL 32611, ++ NZ Applied Technologies, 150-C New Boston St., Woburn, MA 02215

Numerous studies have shown that quantum confinement is at least in part responsible for visible light photoluminescence from porous silicon. Since porous silicon possesses an irregular dendritic structure, it has proven difficult to fabricate reliable and reproducible light emitting devices using this material. Quantum well based devices would alleviate many of the difficulties associated with device production. The large band gap of zinc sulfide and its near lattice match to silicon make it a promising candidate as a barrier material for silicon quantum well devices. Calculations indicate silicon quantum wells with zinc sulfide barriers should emit in the near inhered to visible region of the spectrum for well widths below 100 Å. Growth conditions have been found that allow the epitaxial deposition of silicon and zinc sulfide. Silicon multiple quantum well structures have been deposited with zinc sulfide barriers. Samples have been grown on p type silicon substrates and capped with n type zinc sulfide to allow for carrier injection. Device characterization and testing results will be discussed.

10:00 am Break